test: add bounded first-failure uniform SRT diagnostic

docs/development/refinement_mrt.md

@@ -1,34 +0,0 @@
-# MRT reuse in blocked/refined stepping (candidate)
-
-Base `9805383`. Opt-in by `LBMConfig(collision="MRT")`; SRT remains the default and its
-kernel statements, including the shifted retained-delta/direct-momentum path, are unchanged
-under the alternate compile branch.
-
-## What changes
-- `blocks.cu` (`BlockStep`), `step/block_channel.cu` (`BlockChannelStep`) and `refinement.cu`
-  (`patch_collide`) gain a compile-time `COLLISION_MODEL == 2` branch that repeats the uniform
-  `collide_dispatch` sequence with zero forcing: `compute_rho_u`, omega clamp to
-  `[OMEGA_COLLISION_MIN, OMEGA_COLLISION_MAX]`, `collide_mrt_no_force`.
-- Kernel and host guards accept SRT or MRT only. TRT, LES, non-FP32 storage, non-double-buffer
-  streaming, and shifted dense/mixed refinement remain rejected.
-- Transfers, subcycling, BFL, raw exchange ledgers and channel closures are untouched. The
-  existing pressure-NEQ outlet selects its MRT branch (unknowns-only NEQ extrapolation) from
-  `COLLISION_MODEL`, so MRT channel parity must use uniform MRT as reference.
-
-## Contracts (existing operator, not redefined here)
-- Shifted storage uses the existing MRT representation (equilibrium moments from `rho - 1`),
-  not the SRT retained-delta/direct-momentum precision. Mass and momentum are conserved
-  moments (relaxation rate 0).
-- Kinetic rates are the operator's fixed `s_e = s_eps = s_q = 1.2` on every level; the shear
-  rate is the existing per-level omega. Under acoustic 2:1 scaling the physical bulk viscosity
-  therefore halves on each finer level. No rate rescaling is applied.
-- No LES, no external forcing (`d_params` force fields stay zero).
-- Shifted Jets stay SRT-only: `body/jets.py` keeps its existing guard. This extension does not
-  provide shifted MRT Jets.
-- `PeriodicBlockStepper` (uniform blocked stepper) remains SRT-only.
-
-## Evidence status
-CPU: `tests/unit/test_refinement_mrt.py` (host guards, source contract). GPU:
-`tests/validation/multigrid/test_refinement_mrt_gpu.py` (uniform-MRT channel parity, AMR MRT
-smoke) and unchanged SRT GPU tests. Strict parity may be subject to cross-kernel FMA
-contraction differences already documented for SRT. Not a DFG/benchmark validation.

docs/validation/refined_dfg_mrt.md

@@ -1,71 +0,0 @@
-# Matched MRT DFG pilot preparation
-
-Preparation only: this test-only extension reuses the existing runner and existing MRT
-operator. GPU admission awaits reviewed MRT capability results; no pilot/full execution
-is implied by CPU preflight. No production, historical SRT manifest, reference data,
-periodic gate, geometry, initialization or observation algorithm is changed here.
-
-## Selection and provenance
-
-Use `--collision MRT` for **both** uniform D80 and refined root D40/fine D80. There are
-no independently selectable collision models per case. Default remains SRT.
-
-MRT verifies `data/refined_dfg/source_manifest_mrt.json`, pinned to reviewed numerical
-source snapshot `3ea131e92c057843034f11a1c574301a2430dfce`, including the shared geometry,
-pressure/cycle helpers and official reference. Test-only commits may change HEAD without
-changing this numerical source pin. Plan, READY, case summaries and comparison separately
-record `checkout_revision` and `checkout_dirty` using existing source-provenance helper;
-the runner hash remains separate. Collision is recorded in every receipt, and full-mode
-validation rejects missing or different collision labels in plan, either summary or either
-READY receipt, in addition to existing source/runner/health/time checks.
-
-The historical SRT manifest remains byte-for-byte unchanged. SRT on the MRT candidate
-checkout deliberately fails that source pin; use a matching historical checkout via
-`--source` for SRT. No fallback or automatic repinning is permitted. Historical SRT
-failure/diagnostic evidence remains attached to its original source and runner hashes;
-it cannot authorize an MRT full run. The existing failed-observation step-reporting
-undercount is not changed in this narrowly scoped selection patch.
-
-## Frozen physical comparison
-
-All settings remain those documented in `refined_dfg.md`: U_lattice=.01, physical mean
-U=1 m/s, D=.1 m, shear ν=.001 m²/s, fixed physical domain/body/wall planes, patch
-(40,24,320,140), shifted FP32 double buffers, no LES/forcing/Jets, finest dx=.00125 m,
-finest dt=.0000125 s, unchanged half-cell frame conversion and axis-specific phase.
-Force interval accumulation, physical leaf mass, pressure interpolation, flux sampling,
-safety thresholds, t*=5 pilot and t*=300 cap are unchanged. Existing accuracy/periodicity
-criteria are imported unchanged. Both MRT cases are fresh runs; old MRT or SRT results
-are not substituted as controls.
-
-Both cases use the **existing MRT pressure-NEQ branch**: only unknown directions q2/6/8
-are extrapolated. This differs from SRT's all-nine .5-damped branch; the retained
-`srt_neq_damp=.5` configuration value is inactive under MRT. Backflow clamp remains off.
-The outlet is still noncanonical relative to exact DFG do-nothing conditions.
-
-The reused MRT operator keeps fixed kinetic rates `s_e=s_eps=s_q=1.2` on all levels;
-only the shear rate follows existing per-level viscosity. Physical bulk relaxation
-therefore differs between coarse and fine levels. Transfer operators and subcycling
-are unchanged. This is the candidate's declared behavior, not a new fully mode-scaled
-MRT transfer scheme. Do not tune rates, the patch or gates after seeing outcomes.
-Capability smoke/parity gates do not establish DFG accuracy or speedup.
-
-## CPU and admission commands
-
-From this checkout:
-
-```sh
-python tests/unit/test_refined_dfg.py
-python tests/validation/run_refined_dfg.py --collision MRT --mode plan --output /tmp/new-mrt-dfg-plan
-```
-
-After root verifies the candidate MRT root/parity/refinement capability results and admits
-an idle device, the paired pilot may use the existing bounds and external watchdog:
-
-```sh
-CUDA_VISIBLE_DEVICES=<admitted-device> timeout --signal=TERM --kill-after=30s <hard-budget>s python tests/validation/run_refined_dfg.py --collision MRT --mode pilot --gpu-gates-approved --max-wall-seconds <soft-budget> --output <new-mrt-pilot-directory>
-```
-
-The flag is caller attestation, not evidence. An unhealthy first case prevents the second.
-Existing strict pilot receipt validation and calibrated wall-time controls remain; full
-mode is not being admitted as part of this preparation. Root must review both healthy
-pilot outcomes and separately decide any full-run admission.

docs/validation/refined_dfg_timing.md

@@ -1,58 +0,0 @@
-# Refined DFG MRT timing harness (measurement only)
-
-`tests/validation/time_refined_dfg.py` times the matched MRT refined/uniform DFG Re100 setup of
-`run_refined_dfg.py` (same configuration, geometry and initial state functions). No numerical,
-physics-gate or production change; no force or accuracy result is produced.
-
-| Variant | Loop | Force reads |
-|---|---|---|
-| A | refined `step(1)` + `read_raw_exchange` per base step | runner-like force-read workload (values discarded) |
-| B | refined `step(1)` only, no host reads (`observe_raw_exchange` stays on) | timing-only |
-| C | refined single `step(N)` | timing-only; ledger keeps the final base interval only |
-| E | uniform `sim.run(<=100)` + `read_force` | runner-like force-read workload (values discarded) |
-| E' | uniform single `sim.run(2N)` | timing-only; at most a whole-window average, different summation order |
-
-- No variant retains a valid force history; A/E omit the runner's interval aggregation and
-  validation, and no variant includes macro/probe/CSV costs. Results are not full benchmark
-  throughput.
-- Status lines: `CONSTRUCTED` (construction/JIT complete) and `WARM_READY` (first warm-up and
-  health check passed) per case.
-- Equal simulated duration: N refined base steps vs 2N uniform D80 steps.
-- Every repeat starts from the same fresh state (refined `initialize`, uniform `snapshot/restore`)
-  and the same warm-up; construction/JIT, warm-up, downloads and parity checks are untimed.
-- The actual stepping stream is synchronized explicitly before and after each timed loop; the
-  wall timer (`time.perf_counter`) is the only source. No CUDA-event span is called kernel time.
-- `--max-wall-seconds` is required for GPU runs (outer timeout, checked between variants and
-  every 100 steps in per-step loops).
-- Final populations and NaN masks must be bitwise identical to the first A repeat (A/B/C) or the
-  first E repeat (E/E'); refined and uniform grids are never compared. Leaf/fluid populations
-  must be finite. Physical health (finite leaf/fluid macros, rho in [0.5, 1.5], max Mach <= 0.2,
-  the existing runner limits) is checked after warm-up and after each timed window. Matching NaN
-  is accepted only as a storage mask; any infinity or level-count mismatch fails parity. All
-  parity/health checks are untimed.
-- Cases run sequentially (uniform, then refined) in one process with startup serialized;
-  variants are interleaved within each repeat. A-B and B-C are measured comparative
-  differences under GPU variability, not exact causal decompositions.
-
-Usage (root selects one verified idle GPU):
-
-    PYTHONPATH=src python -m unittest tests/unit/test_time_refined_dfg.py
-    python tests/validation/time_refined_dfg.py --output <new> --plan
-    CUDA_VISIBLE_DEVICES=<gpu> python tests/validation/time_refined_dfg.py --output <new> --max-wall-seconds <s>
-
-Defaults: 2000 base steps, 200 warm-up base steps, 3 repeats. Profiler capture and the
-`observe_raw_exchange=False` variant are deferred until these measurements exist.
-
-## A versus observation-window ledger (`tests/validation/time_window_dfg.py`)
-
-Measurement-only comparison on the same shifted-MRT refined setup: A (per-base `step(1)` +
-`read_raw_exchange`, summed per 80-base-step interval), W (`start_exchange_window`, `step(80)`,
-one window read) and W1 (window with 80 x `step(1)`, isolating the read pattern from call
-batching). Same fresh state, warm-up and simulated duration; populations must be bitwise equal
-to the first A repeat and per-interval total impulses within the documented engineering
-tolerance, all outside timing. The candidate source is recorded (checkout revision, dirty flag,
-file hashes); frozen refined-DFG manifests/results are not used or changed.
-
-    PYTHONPATH=src python -m unittest tests/unit/test_time_window_dfg.py
-    python tests/validation/time_window_dfg.py --output <new> --plan
-    CUDA_VISIBLE_DEVICES=<gpu> python tests/validation/time_window_dfg.py --output <new> --max-wall-seconds <s>

docs/validation/uniform_srt_diagnostic.md

@@ -0,0 +1,52 @@
+# First-failure uniform SRT diagnostic (prepared, not executed)
+
+Purpose: locate the first physical failure in the unchanged uniform D80 SRT control that was healthy at executed step 160 and nonfinite at the next observation, executed step 320. The original failure's summary `steps=160` is the last accepted observation, not the last executed step. This diagnostic does not select different numerical parameters, run an AMR case or perform a new benchmark campaign.
+
+## Exact source and configuration
+
+The default source is the containing repository (override with `--source`); the exact pinned production/runtime source is commit `9805383f9c50d867e8555471baf5dbda8333a652`. The manifest pins production files and the helper/runner dependencies directly against the original failure's `source_before.json`. All pinned contents match. Import guards require CelerisLab and the runner from the selected pinned checkout.
+
+The script calls the original `run_refined_dfg.config(helper,80)` factory and unchanged `Simulation(...).initialize()`. Thus it retains D80, U=.01, ν=.008, τ=.524, ω≈1.9084, shifted FP32, SRT, double buffer, parabolic local Zou–He inlet, all-nine pressure-NEQ damping .5, backflow clamp disabled, identical cylinder geometry and initialization. No clipping, equilibrium rewrite or solver patch is added.
+
+The inlet overload in this source may differ by FP32 rounding from older d79 code even where the algebra matches; that is not changed here and is not established as the cause of failure. MRT's outlet branch also differs. Neither prior MRT success nor this diagnostic establishes an SRT/outlet/body attribution.
+
+## Observation and stop contract
+
+- At most 320 actual solver steps, starting from the original fresh initialization. Stop at the first physical health failure (or wall deadline).
+- Read the production macroscopic path, its decoded populations, and force after every completed step. Preserve the actual executed count separately from the last observed count.
+- Independently report nonfinite physical populations, nonfinite physical macros and nonfinite reaction. Apply the original density [.5,1.5] and Mach≤.2 checks to physical FLUID nodes. A new population-only check may stop earlier than the original macro-only health check; the report explicitly distinguishes it.
+- Per-step `Simulation.run(1)` resets/reads the observation buffer for a one-step force window. This changes observation cadence and force accumulation windows, not configuration or fluid updates. A cumulative-force-only overflow from the original 100/60-step batching would not be reproduced identically; that limitation is explicit. Original macro warnings already show nonfinite populations/macros, so this instrument prioritizes locating the physical failure.
+- Ghost/inactive/body-solid populations are reported in separate categories; their NaNs do not independently trigger physical failure. Category masks are disjoint and complete. Boundary subtypes are decoded as the nibble, not mistaken for independent bit flags.
+- Physical region labels are body-near (within radius+3 cells), outlet/inlet-near (three fluid columns), wall-near (three fluid rows), and remaining bulk. These locate symptoms, not causal mechanisms.
+- Initial, preceding and firstbad/final compact reports retain category counts, finite global extrema and positions, the first 16 offending nodes in row-major order, their bad q indices/all populations, and up to four 5×5 population/flag neighborhoods. “First” identifies earliest sampled step; within that step the list is row-major, not an asserted temporal order among GPU threads.
+
+## Bounded evidence
+
+Only the immediately preceding and firstbad/final active-buffer states are retained. `states.npz` contains their exact raw shifted FP32 values, production-decoded FP32 populations and step numbers, plus flags. This is ~81 MiB at the exact D80 shape, with a 128 MiB artifact limit enforced. There are no saved field trajectories. Initial conditions are reproducible from the source/config; only their diagnostic summary is retained.
+
+These are diagnostic snapshots, not full restart checkpoints (spare buffers and observation/control state are not a restart bundle). `diagnostics.json` stores nonfinite numbers as explicit `NaN`, `+Inf`, `-Inf` strings and is strict finite JSON; NPZ preserves actual IEEE values. A force-only failure can have no offending fluid node. A clean cap means no sampled failure through 320, not benchmark acceptance.
+
+## CPU validation
+
+```sh
+python tests/validation/uniform_srt_diagnostic/test_diagnostic.py
+python tests/validation/uniform_srt_diagnostic/diagnose_uniform_srt.py --output /tmp/new-srt-preflight
+```
+
+Seven CPU-only tests pass: source/config, complete category partition, inactive nonfinite exclusion, independent population/macro/force reasons, health thresholds, bounded two-state artifact writing, and deadline/source guards. `py_compile` and the real-source default preflight pass. No CUDA import is required by preflight/tests and no GPU was executed here.
+
+## Root-only admitted execution
+
+After independent review and root GPU admission:
+
+```sh
+CUDA_VISIBLE_DEVICES=<admitted-device> timeout --signal=TERM --kill-after=30s <hard-budget>s python tests/validation/uniform_srt_diagnostic/diagnose_uniform_srt.py --source <exact-9805383-checkout> --execute --gpu-admitted --wall-seconds <soft-budget> --output <new-output-directory>
+```
+
+The external watchdog is required for a blocked CUDA call; cooperative wall checks cannot interrupt one. Budget should allow per-step downloads and ~81 MiB evidence writing; this diagnostic is not a performance measurement. The step ceiling cannot be increased by a CLI flag. `READY` is emitted after the first completed step and all observation paths. First physical failure is expected diagnostic evidence and returns exit 2; step cap returns 0. `preflight.json` records the pre-execution configuration, not a completion receipt.
+
+Original failure files, production source, original pilot runner and gates are untouched. This test-only handoff is based on exact commit 9805383; added diagnostic files are not part of the historical failure source manifest.
+
+## Historical reporting undercount (not changed here)
+
+The failed pilot executed to step 320 before its second observation failed. Its summary `steps=160` reflects `begin`, which advances only after an accepted observation. This is a reporting undercount, not evidence that the second batch did not execute. The original failure package and runner/gates are preserved unchanged. This diagnostic records both `executed_steps` and `observation_step`, and labels previous-state steps explicitly. Fixing the historical runner's reporting is a separate change.

src/CelerisLab/lbm/channel.py

@@ -1,4 +1,4 @@
-"""Host contract for the blocked root's uniform SRT/MRT channel boundary.
+"""Host contract for the blocked root's uniform-SRT channel boundary.
 
 Boundary ghosts are evolved state, but are not physical fluid leaves. Halo
 ownership remains periodic to reproduce the uniform kernel's wrapped pulls.
@@ -29,7 +29,7 @@ def validate_channel_config(cfg, blocks):
 def validate_channel_transfers(pair, layout, targets):
     """Reject actual exchange/closure overlap, not a padded geometric envelope.
 
-    Explosion donors and restriction receivers must use ordinary bulk collision
+    Explosion donors and restriction receivers must use ordinary bulk SRT
     semantics. Restriction writes receiver-local source slots; these may not
     overwrite the channel's extra immutable-input reads (pressure donor and
     same-node halfway-wall corrections). The slot check deliberately respects

src/CelerisLab/lbm/kernels/blocks.cu

@@ -14,15 +14,12 @@
 #include "core/obs.cuh"
 #include "operators/macro.cuh"
 #include "operators/collision_srt.cuh"
-#if COLLISION_MODEL == 2
-#include "operators/collision_mrt.cuh"
-#endif
 #include "streaming/pull_double_buffer.cuh"
 #include "boundary/curved_boundary.cuh"
 #include "boundary/planar_velocity.cuh"
 
-#if DIM != 2 || NQ != 9 || (COLLISION_MODEL != 0 && COLLISION_MODEL != 2) || STORE_PRECISION != 0 || USE_LES || STREAMING_MODEL != 0
-#error "Blocks require FP32 D2Q9 SRT or MRT double buffers without LES"
+#if DIM != 2 || NQ != 9 || COLLISION_MODEL != 0 || STORE_PRECISION != 0 || USE_LES || STREAMING_MODEL != 0
+#error "Blocks require FP32 D2Q9 SRT double buffers without LES"
 #endif
 
 // Fixed-patch cell kinds, matching refinement.py ACTIVE/INNER_GHOST/OUTER_GHOST.
@@ -144,13 +141,6 @@ extern "C" __global__ void BlockStep(const fpxx* in, fpxx* out, unsigned int hal
                         gx, d_block_wall.nx, d_block_wall.slot_width, d_block_wall.amplitude));
                 else if (gy == d_block_wall.ny - 2) reconstruct_top_reservoir(f, RHO);
             }
-#if COLLISION_MODEL == 2
-            // Uniform MRT sequence (collide_dispatch, zero forcing); SRT path below unchanged.
-            float rho, ux, uy;
-            compute_rho_u(f, rho, ux, uy);
-            collide_mrt_no_force(f, rho, ux, uy,
-                fminf(OMEGA_COLLISION_MAX, fmaxf(OMEGA_COLLISION_MIN, d_params.omega)));
-#else
             float rho, ux, uy, feq[NQ];
             compute_rho_u(f, rho, ux, uy);
 #if USE_DDF_SHIFTING
@@ -163,7 +153,6 @@ extern "C" __global__ void BlockStep(const fpxx* in, fpxx* out, unsigned int hal
             compute_feq(rho, ux, uy, feq);
 #endif
             collide_srt_no_force(f, feq, d_params.omega);
-#endif
         }
     }
     stream_pull_store(k, f, out + base);

src/CelerisLab/lbm/kernels/refinement.cu

@@ -11,9 +11,6 @@
 #include "core/obs.cuh"
 #include "operators/macro.cuh"
 #include "operators/collision_srt.cuh"
-#if COLLISION_MODEL == 2
-#include "operators/collision_mrt.cuh"
-#endif
 #include "streaming/pull_double_buffer.cuh"
 #include "boundary/planar_velocity.cuh"
 #include "boundary/curved_boundary.cuh"
@@ -22,8 +19,8 @@ extern "C" {
 #include "step/curved_double.cu"
 }
 
-#if DIM != 2 || NQ != 9 || (COLLISION_MODEL != 0 && COLLISION_MODEL != 2) || STORE_PRECISION != 0 || USE_DDF_SHIFTING || USE_LES || STREAMING_MODEL != 0
-#error "Refinement requires unshifted FP32 D2Q9 SRT or MRT double buffers without LES"
+#if DIM != 2 || NQ != 9 || COLLISION_MODEL != 0 || STORE_PRECISION != 0 || USE_DDF_SHIFTING || USE_LES || STREAMING_MODEL != 0
+#error "Refinement requires unshifted FP32 D2Q9 SRT double buffers without LES"
 #endif
 
 // Enabled only in the validation build; no diagnostic arrays in normal builds.
@@ -36,17 +33,10 @@ __device__ unsigned int incoming_counts[NQ * TOTAL_CELLS];
 #endif
 
 __device__ __forceinline__ void patch_collide(float* f, unsigned long k) {
-#if COLLISION_MODEL == 2
-    float rho, ux, uy;
-    compute_rho_u(f, rho, ux, uy);
-    collide_mrt_no_force(f, rho, ux, uy,
-        fminf(OMEGA_COLLISION_MAX, fmaxf(OMEGA_COLLISION_MIN, d_params.omega)));
-#else
     float rho, ux, uy, feq[NQ];
     compute_rho_u(f, rho, ux, uy);
     compute_feq(rho, ux, uy, feq);
     collide_srt_no_force(f, feq, d_params.omega);
-#endif
 #ifdef CELERIS_REFINEMENT_AUDIT
     ++collision_counts[k];
 #endif

src/CelerisLab/lbm/kernels/step/block_channel.cu

@@ -54,20 +54,12 @@ extern "C" __global__ void BlockChannelStep(
             f[7] = load_ddf(in + base, index_f(k, 8));
         }
         if (!wall && !outlet) {
-#if COLLISION_MODEL == 2
-            // Match uniform MRT arithmetic (collide_dispatch, zero forcing).
-            float rho, ux, uy;
-            compute_rho_u(f, rho, ux, uy);
-            collide_mrt_no_force(f, rho, ux, uy,
-                fminf(OMEGA_COLLISION_MAX, fmaxf(OMEGA_COLLISION_MIN, d_params.omega)));
-#else
             // Match uniform SRT arithmetic, including its shifted equilibrium path.
             float rho, ux, uy, feq[NQ], forcing[NQ] = {};
             compute_rho_u(f, rho, ux, uy);
             compute_feq(rho, ux, uy, feq);
             const float omega = fminf(OMEGA_COLLISION_MAX, fmaxf(OMEGA_COLLISION_MIN, d_params.omega));
             collide_srt(f, feq, forcing, omega);
-#endif
         }
     }
     stream_pull_store(k, f, out + base);

src/CelerisLab/lbm/raw_exchange.py

@@ -7,26 +7,16 @@ import numpy as np
 
 
 def summarize_exchange(rows, body_ids, aperture, *, body_id, level, h,
-                       time_end, window, reference_center, duration=None):
+                       time_end, window, reference_center):
     """Reduce FP64 interval integrals or convert FP32 last-substep raw rows.
 
     dt_l=h_l under acoustic 2:1 refinement. Local momentum j -> base force
     h*j -> impulse h*dt*j; torque adds one h; mass is h**2*dm.
-    window="window" reduces an FP64 observation-window ledger spanning
-    ``duration`` (integer >= 1) base intervals; rates divide by that duration.
     """
-    if window not in ("last_base_step", "last_substep", "window"):
+    if window not in ("last_base_step", "last_substep"):
         raise ValueError("unknown exchange window")
-    if window == "window":
-        if isinstance(duration, bool) or not isinstance(duration, (int, np.integer)) or duration < 1:
-            raise ValueError("window duration must be an integer number of base intervals >= 1")
-    elif duration is not None:
-        raise ValueError("duration applies only to window='window'")
     values = np.array(rows, dtype=np.float64, copy=True)
-    if window == "window":
-        duration = float(duration)
-    else:
-        duration = 1.0 if window == "last_base_step" else h
+    duration = 1.0 if window == "last_base_step" else h
     if window == "last_substep":
         values *= np.array([h*h, h*h, h*h*h, h*h])
     selected = np.asarray(body_ids) == body_id
@@ -41,7 +31,6 @@ def summarize_exchange(rows, body_ids, aperture, *, body_id, level, h,
     return dict(wall=reduce(selected & ~aperture), aperture=reduce(selected & aperture),
                 total=reduce(selected), body_id=int(body_id), level=int(level),
                 time_start=time_end-duration, time_end=time_end, dt=h,
-                sample_count=(round(duration/h) if window == "window"
-                              else round(1/h) if window == "last_base_step" else 1),
+                sample_count=round(1/h) if window == "last_base_step" else 1,
                 window=window, units="base_lattice_per_unit_depth",
                 definition="raw_boundary_exchange", reference_center=tuple(reference_center), valid=True)

src/CelerisLab/lbm/refinement.py

@@ -52,17 +52,17 @@ class FixedPatch2D:
     def from_config(cls, cfg: LBMConfig, bounds) -> "FixedPatch2D":
         """Prepare maps without changing cfg or allocating coarse-sized tables.
 
-        The backend contract is D2Q9/SRT or MRT/FP32/double_buffer,
+        The initial backend contract is D2Q9/SRT/FP32/double_buffer,
         without LES. Two coarse cells of margin keep all halo donors in bounds;
         this does NOT certify that those donors are fluid or periodic.
         """
         checked = replace(cfg)
         checked.validate()
-        if (not checked.is_d2q9 or checked.collision not in ("SRT", "MRT")
+        if (not checked.is_d2q9 or checked.collision != "SRT"
                 or checked.streaming != "double_buffer"
                 or checked.store_precision != "FP32"
                 or checked.les_enabled):
-            raise ValueError("FixedPatch2D requires D2Q9/SRT or MRT/FP32/double_buffer without LES")
+            raise ValueError("FixedPatch2D requires D2Q9/SRT/FP32/double_buffer without LES")
         bounds = tuple(bounds)
         if len(bounds) != 4 or any(isinstance(v, (bool, np.bool_))
                                    or not isinstance(v, Integral) for v in bounds):
@@ -451,7 +451,7 @@ def prepare_fine_boundary(cfg, patch, objects, *, wall_aware=False, jets=(),
     checked = replace(cfg)
     checked.validate()
     if (patch.coarse_shape != (cfg.ny, cfg.nx) or not checked.is_d2q9
-            or checked.collision not in ("SRT", "MRT") or checked.streaming != "double_buffer"
+            or checked.collision != "SRT" or checked.streaming != "double_buffer"
             or checked.store_precision != "FP32" or checked.les_enabled
             or patch.tau_coarse != 3*checked.viscosity+.5):
         raise ValueError("Fine boundary requires the matching fixed-patch configuration")

src/CelerisLab/lbm/refinement_stepper.py

@@ -172,9 +172,6 @@ class FixedPatchStepper:
     base interval or last substep in base-lattice units per unit depth. This
     is boundary momentum reaction, not a validated nozzle/stress load. Dense
     body layouts are not supported by this new diagnostic in this candidate.
-    ``observe_window_exchange=True`` (requires observe_raw_exchange) adds a second
-    per-link FP64 ledger accumulated by the same kernel between
-    start_exchange_window() and read_exchange_window(); disabled by default.
     ``jets`` (body.jets.Jet) use the same edge frame as ``fine_objects`` and
     drive fine cut links selected at their true hits; ``set_jet_amplitude``
     re-uploads the per-link velocity column only.
@@ -219,7 +216,7 @@ class FixedPatchStepper:
                  fine_block=None, base_block=None, jets=(), child=None, child_block=None,
                  child_objects=(), child_jets=(), child_rectangles_in_parent=None,
                  refinements=None, level_blocks=None, level_objects=None, level_jets=None,
-                 observe_raw_exchange=False, observe_window_exchange=False):
+                 observe_raw_exchange=False):
         if HALO != 4:
             raise RuntimeError("refinement.cu requires a four-cell fine halo")
         if coarse_boundary not in ("periodic", "slot_reservoir", "channel"):
@@ -318,13 +315,6 @@ class FixedPatchStepper:
                                       for b, layout in zip(self._boundary_hosts, self._layouts)):
             raise ValueError("raw exchange currently requires blocked body levels")
         self._observe_raw_exchange = observe_raw_exchange
-        if not isinstance(observe_window_exchange, bool):
-            raise ValueError("observe_window_exchange must be bool")
-        if observe_window_exchange and not observe_raw_exchange:
-            raise ValueError("observe_window_exchange requires observe_raw_exchange")
-        self._observe_window = observe_window_exchange
-        self._window_valid = False
-        self._window_start = None
         self._exchange_valid = False
         self._exchange_spacing = tuple(spacings)
         self._exchange_centers = tuple(tuple(tuple(o.geometry.center) for o in objects)
@@ -375,8 +365,6 @@ class FixedPatchStepper:
                             count = len(b.tables["cell"])
                             b.last_raw = self._allocate(count * 4 * 4)
                             b.interval_integral = self._allocate(count * 4 * 8)
-                            if self._observe_window:
-                                b.window_integral = self._allocate(count * 4 * 8)
                             b.accumulate = level.module.get_function("BlockAccumulateExchange")
                         b.kernel = level.module.get_function("BlockCurvedBoundary")
                 if self._level_boundaries[1] is not None:
@@ -571,7 +559,6 @@ class FixedPatchStepper:
                     cuda.memset_d8(self._fine_curved.link_exchange_gpu, 0, self._fine_curved.count * 12)
                 self._step_count = 0
                 self._exchange_valid = False
-                self._window_valid = False
                 self._status = "ready"
             except BaseException:
                 self._status = "failed"
@@ -652,8 +639,7 @@ class FixedPatchStepper:
                 fine_block=fine_block, child_block=child_block,
                 child_rectangles_in_parent=new.child.bounds,
                 child_objects=child_objects, child_jets=jets,
-                observe_raw_exchange=self._observe_raw_exchange,
-                observe_window_exchange=self._observe_window)
+                observe_raw_exchange=self._observe_raw_exchange)
             try:
                 if self._ddf_shifting:
                     candidate._initialize_raw(_StoredPopulations(transferred.g, transferred.shifted))
@@ -785,10 +771,6 @@ class FixedPatchStepper:
             b.accumulate(b.last_raw, b.interval_integral, np.uint32(count),
                          np.float64(h), np.float64(h),
                          grid=((count + self._block[0] - 1) // self._block[0], 1), **kw)
-            if self._window_valid and b.window_integral is not None:
-                b.accumulate(b.last_raw, b.window_integral, np.uint32(count),
-                             np.float64(h), np.float64(h),
-                             grid=((count + self._block[0] - 1) // self._block[0], 1), **kw)
         flags = np.uintp(0) if level.boundary is None else level.boundary.flags
         level.kernel(src, dst, np.uint32(level.layout.halo), flags, level.kind, grid=level.grid, **kw)
 
@@ -822,57 +804,9 @@ class FixedPatchStepper:
                     self._exchange_valid = self._observe_raw_exchange
                 self._status = "ready"
             except BaseException:
-                self._window_valid = False
                 self._status = "failed"
                 raise
 
-    def start_exchange_window(self):
-        """Zero the window ledgers and open a window at the current completed step count."""
-        with self._lock, self.ctx.activate():
-            self._require("ready")
-            if not self._observe_window:
-                raise RuntimeError("window exchange observation is disabled")
-            self._window_valid = False
-            try:
-                for b in self._level_boundaries:
-                    if b is not None and b.window_integral is not None:
-                        cuda.memset_d8(b.window_integral, 0, len(b.tables["cell"]) * 32)
-            except BaseException:
-                self._status = "failed"
-                raise
-            self._window_start = self._step_count
-            self._window_valid = True
-
-    def read_exchange_window(self, body_id, *, level=1):
-        """Non-destructive read of [window start, current step count] in base-lattice units."""
-        with self._lock, self.ctx.activate():
-            self._require("ready")
-            if not self._observe_window:
-                raise RuntimeError("window exchange observation is disabled")
-            if not self._window_valid:
-                raise RuntimeError("no valid exchange window; call start_exchange_window()")
-            duration = self._step_count - self._window_start
-            if duration < 1:
-                raise RuntimeError("exchange window requires at least one completed base interval")
-            if (isinstance(level, bool) or not isinstance(level, Integral)
-                    or not 0 <= level < len(self._levels)):
-                raise ValueError("level must name an existing level")
-            b = self._level_boundaries[level]
-            if (b is None or isinstance(body_id, bool) or not isinstance(body_id, Integral)
-                    or not 0 <= body_id < len(b.host.objects)):
-                raise ValueError("body_id must name a body on this level")
-            rows = np.empty((len(b.tables["cell"]), 4), np.float64)
-            try:
-                cuda.memcpy_dtoh(rows, b.window_integral)
-            except BaseException:
-                self._status = "failed"
-                raise
-            return summarize_exchange(rows, b.tables["body_id"], b.tables["aperture"],
-                                      body_id=body_id, level=level, h=self._exchange_spacing[level],
-                                      time_end=self._step_count, window="window",
-                                      reference_center=self._exchange_centers[level][body_id],
-                                      duration=duration)
-
     def read_raw_exchange(self, body_id, *, level=1, window="last_base_step"):
         """Read raw boundary reaction about its geometric center in the root edge frame.
 
@@ -951,7 +885,6 @@ class FixedPatchStepper:
                     if b is not None:
                         b.flags = b.device = b.kernel = None
                         b.last_raw = b.interval_integral = b.accumulate = None
-                        b.window_integral = None
                 self._levels.clear()
                 self._pairs = []
                 if getattr(self, "_fine_curved", None) is not None:

src/CelerisLab/lbm/refinement_tables.py

@@ -85,7 +85,6 @@ class _BlockedBoundary:
     last_raw: object = None
     interval_integral: object = None
     accumulate: object = None
-    window_integral: object = None  # optional observation-window FP64 ledger
 
 
 def _prepare_blocked_boundary(boundary, layout, cfg, jets, *, _shifted_blocked=False):

tests/unit/test_raw_exchange_window.py

@@ -1,45 +0,0 @@
-"""Host reduction contract for the optional observation-window exchange ledger."""
-import unittest
-
-import numpy as np
-
-from CelerisLab.lbm.raw_exchange import summarize_exchange
-
-
-def reduce(rows, window, duration=None, h=.5, time_end=10):
-    return summarize_exchange(rows, np.array([0, 0, 1]), np.array([False, True, False]),
-                              body_id=0, level=1, h=h, time_end=time_end, window=window,
-                              reference_center=(0., 0.), duration=duration)
-
-
-class ExchangeWindowReduction(unittest.TestCase):
-    def test_window_duration_scaling(self):
-        rows = np.array([[1., 2., 3., 4.], [.5, -1., 0., 1.], [9., 9., 9., 9.]])
-        out = reduce(rows, "window", duration=4)
-        np.testing.assert_array_equal(out["total"]["impulse"], [1.5, 1.])
-        np.testing.assert_array_equal(out["total"]["force"], [1.5 / 4, 1. / 4])
-        self.assertEqual(out["total"]["torque"], 3. / 4)
-        self.assertEqual(out["total"]["mass_rate"], 5. / 4)
-        np.testing.assert_array_equal(out["aperture"]["impulse"], [.5, -1.])
-        self.assertEqual((out["time_start"], out["time_end"]), (6., 10))
-        self.assertEqual(out["sample_count"], 8)  # duration / h fine substeps
-        self.assertEqual(out["window"], "window")
-
-    def test_existing_windows_unchanged(self):
-        rows = np.array([[1., 2., 3., 4.], [0., 0., 0., 0.], [0., 0., 0., 0.]])
-        base = reduce(rows, "last_base_step")
-        self.assertEqual((base["time_start"], base["sample_count"]), (9., 2))
-        np.testing.assert_array_equal(base["total"]["force"], [1., 2.])
-        sub = reduce(rows, "last_substep")
-        self.assertEqual(sub["sample_count"], 1)
-
-    def test_duration_validation(self):
-        rows = np.zeros((3, 4))
-        for bad in (None, 0, -1, 1.5, True):
-            with self.subTest(duration=bad), self.assertRaises(ValueError):
-                reduce(rows, "window", duration=bad)
-        with self.assertRaises(ValueError):
-            reduce(rows, "last_base_step", duration=2)
-
-
-if __name__ == "__main__": unittest.main()

tests/unit/test_refined_dfg.py

@@ -13,11 +13,7 @@ h, periodic = r.helpers(r.DEFAULT_SOURCE)
 
 
 def test_source_pin():
-    historical = json.loads((r.HERE / "data/refined_dfg/source_manifest.json").read_text())
-    assert historical["commit"].startswith("cd3a657")
-    assert r.verify_source(r.DEFAULT_SOURCE, "MRT")["commit"].startswith("3ea131e")
-    with unittest.TestCase().assertRaisesRegex(RuntimeError, "Source mismatch"):
-        r.verify_source(r.DEFAULT_SOURCE, "SRT")
+    assert r.verify_source(r.DEFAULT_SOURCE)["commit"].startswith("cd3a657")
 
 
 def test_matched_units_and_planes():
@@ -139,17 +135,16 @@ def test_axis_specific_sampling_phase():
 
 def test_full_requires_completed_pilot():
     with unittest.TestCase().assertRaisesRegex(ValueError, "pilot-results"):
-        r.verify_pilot(None, r.verify_source(r.DEFAULT_SOURCE, "MRT"))
+        r.verify_pilot(None, r.verify_source(r.DEFAULT_SOURCE))
 
 
 def pilot_fixture(path):
     """Synthetic contract fixture only; never a physical result or run receipt."""
-    manifest = r.verify_source(r.DEFAULT_SOURCE, "MRT")
+    manifest = r.verify_source(r.DEFAULT_SOURCE)
     (path / "plan.json").write_text(
         json.dumps(
             dict(
                 source_manifest=manifest,
-                collision="MRT",
                 bounds_root_edge=list(r.BOUNDS),
                 runner_sha256=r.runner_hash(),
             )
@@ -182,7 +177,6 @@ def pilot_fixture(path):
             json.dumps(
                 dict(
                     case=case,
-                    collision="MRT",
                     mode="pilot",
                     status="pilot_complete",
                     healthy=True,
@@ -198,7 +192,6 @@ def pilot_fixture(path):
             json.dumps(
                 dict(
                     case=case,
-                    collision="MRT",
                     mode="pilot",
                     step=interval,
                     runner_sha256=r.runner_hash(),
@@ -215,7 +208,7 @@ def test_pilot_validation_and_calibration():
     with TemporaryDirectory() as tmp:
         path = Path(tmp)
         manifest = pilot_fixture(path)
-        assert r.verify_pilot(path, manifest, "MRT") == 3606.0
+        assert r.verify_pilot(path, manifest) == 3606.0
 
 
 def test_reject_malformed_pilot_receipts():
@@ -245,7 +238,7 @@ def test_reject_malformed_pilot_receipts():
             mutate(bad)
             receipt.write_text(json.dumps(bad))
             with unittest.TestCase().assertRaises(ValueError):
-                r.verify_pilot(path, manifest, "MRT")
+                r.verify_pilot(path, manifest)
         # Exact reviewer regression: previously accepted NaN endpoint.
         receipt.write_text(
             json.dumps(
@@ -257,11 +250,11 @@ def test_reject_malformed_pilot_receipts():
             )
         )
         with unittest.TestCase().assertRaises(ValueError):
-            r.verify_pilot(path, manifest, "MRT")
+            r.verify_pilot(path, manifest)
         receipt.write_text(json.dumps(valid))
         (path / "uniform/ready.json").write_text("{}")
         with unittest.TestCase().assertRaises(ValueError):
-            r.verify_pilot(path, manifest, "MRT")
+            r.verify_pilot(path, manifest)
 
 
 def test_strict_finite_json_and_deadline():
@@ -290,51 +283,6 @@ def test_pressure_probes_actual_body_mask():
     assert h.pressure_probes(np.ones(pair.fine_shape), fluid, p)["dp"] == 0.0
 
 
-def test_matched_mrt_selection():
-    for diameter in (40, 80):
-        srt, sbody, sp = r.config(h, diameter)
-        mrt, mbody, mp = r.config(h, diameter, "MRT")
-        assert mrt["method"]["collision"] == "MRT"
-        mrt["method"]["collision"] = "SRT"
-        assert mrt == srt and mbody == sbody and mp == sp
-    srt_plan, mrt_plan = r.plan(h), r.plan(h, "MRT")
-    for key in ("root", "uniform", "bounds_root_edge", "finest_dx_m", "finest_dt_s"):
-        assert srt_plan[key] == mrt_plan[key]
-    assert "q2/6/8" in mrt_plan["outlet"] and "all nine" in srt_plan["outlet"]
-    cfg, pair, _, host = r.host_geometry(r.DEFAULT_SOURCE, h, "MRT")
-    assert cfg.collision == "MRT" and pair.fine_shape == (240, 568)
-    assert len(host.boundary_cells) > 0
-
-
-def test_reject_collision_receipts():
-    from tempfile import TemporaryDirectory
-
-    for rel in ("plan.json", "uniform/summary.json", "refined/summary.json",
-                "uniform/ready.json", "refined/ready.json"):
-        for invalid in ("SRT", None):
-            with TemporaryDirectory() as tmp:
-                path = Path(tmp)
-                manifest = pilot_fixture(path)
-                receipt = path / rel
-                record = json.loads(receipt.read_text())
-                if invalid is None:
-                    record.pop("collision")
-                else:
-                    record["collision"] = invalid
-                receipt.write_text(json.dumps(record))
-                with unittest.TestCase().assertRaises(ValueError):
-                    r.verify_pilot(path, manifest, "MRT")
-
-
-def test_record_actual_checkout_separately():
-    from source_provenance import checkout_provenance
-
-    actual = checkout_provenance(r.DEFAULT_SOURCE)
-    assert len(actual["checkout_revision"]) == 40
-    assert isinstance(actual["checkout_dirty"], bool)
-    assert r.verify_source(r.DEFAULT_SOURCE, "MRT")["production_origin_commit"].startswith("3ea131e")
-
-
 if __name__ == "__main__":
     suite = unittest.TestSuite(
         unittest.FunctionTestCase(fn)

tests/unit/test_refinement.py

@@ -142,7 +142,7 @@ class FixedPatchTests(unittest.TestCase):
                 FixedPatch2D.from_config(LBMConfig(nx=nx, ny=ny, viscosity=.1), bounds)
 
     def test_unsupported_backend_and_fine_relaxation_rejected(self):
-        for kwargs in ({"collision": "TRT"}, {"streaming": "esopull"},
+        for kwargs in ({"collision": "TRT"}, {"collision": "MRT"}, {"streaming": "esopull"},
                        {"les_enabled": True},
                        {"store_precision": "FP16S"}, {"lattice_model": "D3Q19"},
                        {"data_type": "FP64"}, {"omega_min": 1.0}):

tests/unit/test_refinement_mrt.py

@@ -1,44 +0,0 @@
-"""Host guards and source contract for MRT reuse in refined/blocked stepping (no CUDA)."""
-from pathlib import Path
-import unittest
-
-from CelerisLab.config import LBMConfig
-from CelerisLab.lbm.refinement import FixedPatch2D
-
-KERNELS = Path(__file__).resolve().parents[2] / "src/CelerisLab/lbm/kernels"
-BOUNDS = (8, 6, 16, 14)
-
-
-class RefinementMRTHost(unittest.TestCase):
-    def test_patch_accepts_implemented_models(self):
-        for collision in ("SRT", "MRT"):
-            with self.subTest(collision=collision):
-                FixedPatch2D.from_config(LBMConfig(nx=24, ny=20, viscosity=.1, collision=collision), BOUNDS)
-
-    def test_patch_rejects_unimplemented(self):
-        for options in (dict(collision="TRT"), dict(collision="MRT", les_enabled=True)):
-            with self.subTest(options=options), self.assertRaises(ValueError):
-                FixedPatch2D.from_config(LBMConfig(nx=24, ny=20, viscosity=.1, **options), BOUNDS)
-
-    def test_srt_statements_and_guards_preserved(self):
-        """MRT is an additive compile-time branch; SRT statements and other guards remain."""
-        blocks = (KERNELS / "blocks.cu").read_text()
-        channel = (KERNELS / "step/block_channel.cu").read_text()
-        refinement = (KERNELS / "refinement.cu").read_text()
-        for text in ("compute_feq_from_momentum(drho, jx, jy, ux, uy, feq);",
-                     "compute_feq(rho, ux, uy, feq);",
-                     "collide_srt_no_force(f, feq, d_params.omega);"):
-            self.assertIn(text, blocks)
-        self.assertIn("collide_srt(f, feq, forcing, omega);", channel)
-        self.assertIn("collide_srt_no_force(f, feq, d_params.omega);", refinement)
-        for source in (blocks, refinement):
-            self.assertIn("(COLLISION_MODEL != 0 && COLLISION_MODEL != 2)", source)
-            self.assertIn("USE_LES", source)
-            self.assertIn("STORE_PRECISION != 0", source)
-            self.assertIn('#if COLLISION_MODEL == 2\n#include "operators/collision_mrt.cuh"\n#endif', source)
-        self.assertIn("USE_DDF_SHIFTING ||", refinement)  # dense/mixed shifted stays rejected
-        for source in (blocks, channel, refinement):
-            self.assertEqual(source.count("collide_mrt_no_force("), 1)
-
-
-if __name__ == "__main__": unittest.main()

tests/unit/test_time_refined_dfg.py

@@ -1,86 +0,0 @@
-"""CPU contract of the measurement-only refined DFG timing harness (no CUDA)."""
-from pathlib import Path
-import sys
-import unittest
-
-import numpy as np
-
-sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "validation"))
-import time_refined_dfg as t  # noqa: E402
-
-
-class TimingHarnessContract(unittest.TestCase):
-    def test_equal_simulated_duration(self):
-        s = t.schedule(2000, 200)
-        self.assertEqual(s["refined"], (200, 2000))
-        self.assertEqual(s["uniform"], (400, 4000))  # one refined base step = two D80 steps
-        self.assertAlmostEqual(s["tstar_window"], 2000 * .01 / 40)
-        for bad in ((0, 1), (1, -1)):
-            with self.assertRaises(ValueError):
-                t.schedule(*bad)
-
-    def test_timing_only_labels(self):
-        for name in ("B", "C", "E'"):
-            self.assertFalse(t.VARIANTS[name]["force_history_valid"])
-            self.assertTrue(t.VARIANTS[name]["timing_only"])
-        for name in ("A", "E"):
-            self.assertFalse(t.VARIANTS[name]["force_history_valid"])  # reads discarded
-            self.assertTrue(t.VARIANTS[name]["force_reads"])
-            self.assertIn("runner-like", t.VARIANTS[name]["force_note"])
-        self.assertEqual({v["case"] for v in t.VARIANTS.values()}, {"refined", "uniform"})
-        self.assertIn("final base interval", t.VARIANTS["C"]["force_note"])
-        self.assertIn("whole-window", t.VARIANTS["E'"]["force_note"])
-
-    def test_deadline(self):
-        import time
-        with self.assertRaises(TimeoutError):
-            t.check_deadline(time.monotonic() - 1)
-        t.check_deadline(time.monotonic() + 60)
-
-    def test_parity_detects_bits_and_nan_masks(self):
-        a = np.array([[1., np.nan], [2., 3.]], np.float32)
-        self.assertIsNone(t.same_state([a], [a.copy()]))
-        b = a.copy(); b[1, 1] = np.nextafter(np.float32(3), np.float32(4))
-        self.assertIn("bits", t.same_state([a], [b]))
-        c = a.copy(); c[0, 0] = np.nan
-        self.assertIn("NaN", t.same_state([a], [c]))
-        self.assertIn("level count", t.same_state([a], [a, a]))
-        inf = a.copy(); inf[1, 0] = np.inf
-        self.assertIn("infinite", t.same_state([inf], [inf.copy()]))  # matching inf still fails
-        self.assertIn("infinite", t.same_state([a], [inf]))
-
-    def test_flat_uniform_ddf(self):
-        fluid = np.array([[True, False, True], [True, True, False]])
-        flat = np.ones(9 * fluid.size, np.float32)  # Simulation.get_ddf() layout
-        self.assertTrue(t.uniform_populations_finite(flat, fluid))
-        flat[1 * fluid.size + 1] = np.nan  # q=1, solid cell 1: ignored
-        self.assertTrue(t.uniform_populations_finite(flat, fluid))
-        flat[4 * fluid.size + 0] = np.nan  # q=4, fluid cell 0: detected
-        self.assertFalse(t.uniform_populations_finite(flat, fluid))
-        self.assertTrue(t.uniform_populations_finite(np.ones((9,) + fluid.shape), fluid))
-        with self.assertRaises(RuntimeError):
-            t.uniform_populations_finite(np.ones(9 * fluid.size + 1), fluid)
-
-    def test_physical_health_limits(self):
-        ok = (np.array([1., 1.01]), np.array([.01, .02]), np.array([0., .01]))
-        health = t.physical_health([ok])
-        self.assertAlmostEqual(health["rho_max"], 1.01)
-        for bad in ((np.array([1., np.nan]),) + ok[1:],
-                    (np.array([.4, 1.]),) + ok[1:],
-                    (ok[0], np.array([.2, 0.]), ok[2]),
-                    (np.array([]), np.array([]), np.array([]))):
-            with self.assertRaises(RuntimeError):
-                t.physical_health([bad])
-
-    def test_summary_reports_differences_without_claims(self):
-        rows = [dict(variant=v, seconds=s) for v, s in
-                (("A", 3.), ("A", 5.), ("B", 2.), ("C", 1.), ("E", 2.), ("E'", 1.5))]
-        s = t.summarize(rows, .5)
-        self.assertEqual(s["A"]["median_seconds"], 4.)
-        self.assertEqual(s["A_minus_B_seconds"], 2.)
-        self.assertEqual(s["B_minus_C_seconds"], 1.)
-        self.assertEqual(s["A_over_E"], 2.)
-        self.assertIn("not exact causal", s["interpretation"])
-
-
-if __name__ == "__main__": unittest.main()

tests/unit/test_time_window_dfg.py

@@ -1,38 +0,0 @@
-"""CPU contract of the A-versus-window timing harness (no CUDA)."""
-from pathlib import Path
-import sys
-import unittest
-
-import numpy as np
-
-sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "validation"))
-import time_window_dfg as w  # noqa: E402
-
-
-class WindowTimingContract(unittest.TestCase):
-    def test_interval_and_variants(self):
-        self.assertEqual(w.INTERVAL, 80)
-        self.assertEqual(w.VARIANTS, ("A", "W", "W1"))
-
-    def test_components(self):
-        obs = dict(total=dict(impulse=np.array([1., 2.]), angular_impulse=3., mass_into_fluid=4.))
-        np.testing.assert_array_equal(w.components(obs), [1., 2., 3., 4.])
-
-    def test_interval_comparison(self):
-        ref = np.array([[1., -1., 0., 0.]])
-        scale = np.array([[10., 10., 1., 1.]])
-        self.assertEqual(w.compare_intervals(ref, scale, ref.copy()), 0.)
-        near = ref + np.array([[5e-9, 0., 0., 0.]])
-        self.assertLessEqual(w.compare_intervals(ref, scale, near), 1.)
-        far = ref + np.array([[1e-7, 0., 0., 0.]])
-        self.assertGreater(w.compare_intervals(ref, scale, far), 1.)
-        zero = np.zeros((1, 4))
-        self.assertGreater(w.compare_intervals(zero, zero, zero + 1e-12), 1.)  # floor, no div-by-0
-
-    def test_candidate_identity_records_files(self):
-        identity = w.candidate_identity(Path(__file__).resolve().parents[2])
-        self.assertIn("checkout_revision", identity)
-        self.assertEqual(set(identity["sha256"]), set(w.CANDIDATE_FILES))
-
-
-if __name__ == "__main__": unittest.main()

tests/validation/multigrid/test_exchange_window.py

@@ -1,260 +0,0 @@
-"""Optional observation-window exchange ledger: host contract (mocked driver) and GPU gate.
-
-Run CPU and GPU classes in separate processes; GPU callers select the device.
-ExchangeWindowGPU uses the SRT/unshifted Jet fixture; ExchangeWindowShiftedMRTGPU covers a
-shifted MRT, all-blocked, stationary-body case without Jets (no shifted-MRT Jet claim).
-GPU tolerance (conservative engineering tolerance, not a universal proof): the window ledger
-sums h*dt*raw per link over fine substeps, while the reference sums per-base interval ledgers
-over links and then over base steps. Both are FP64 reorderings of the same FP32-exact substep
-contributions, so the scale is the sum of the ACTUAL absolute substep contributions (read from
-last_raw after every fine hop), not of per-base totals that could hide substep cancellation:
-|window - reference| <= 4 * m * eps * sum|substep terms| + 1e-300, m = links * substeps.
-"""
-from contextlib import ExitStack
-import unittest
-from unittest.mock import patch
-
-import numpy as np
-import pycuda.driver as cuda
-
-from CelerisLab.lbm.refinement_stepper import FixedPatchStepper
-from test_refinement_blocked_base import mocked_backend
-from test_refinement_blocked_fine import BOUNDS, circle, config
-
-EPS = np.finfo(np.float64).eps
-
-
-def build(m, window=True, raw=True):
-    return FixedPatchStepper(config("periodic"), BOUNDS, context=m["context"], base_block=(3, 4),
-                             fine_block=(16, 20), fine_objects=[circle()],
-                             observe_raw_exchange=raw, observe_window_exchange=window)
-
-
-def same_bits(test, a, b):
-    """Identical NaN masks, no infinities, identical finite FP32 bits (incl. signed zero)."""
-    a, b = np.asarray(a), np.asarray(b)
-    test.assertEqual(a.dtype, b.dtype)
-    test.assertFalse(np.isinf(a).any() or np.isinf(b).any())
-    np.testing.assert_array_equal(np.isnan(a), np.isnan(b))
-    finite = np.isfinite(a)
-    np.testing.assert_array_equal(a[finite].view(np.uint32), b[finite].view(np.uint32))
-
-
-def accumulations(m):
-    return [c for c in m["calls"] if c[0] == "BlockAccumulateExchange"]
-
-
-class ExchangeWindowCPU(unittest.TestCase):
-    def test_constructor_validation(self):
-        with mocked_backend() as m:
-            with self.assertRaisesRegex(ValueError, "requires observe_raw_exchange"):
-                build(m, window=True, raw=False)
-            with self.assertRaisesRegex(ValueError, "must be bool"):
-                build(m, window=1)
-
-    def test_state_machine_and_launches(self):
-        with mocked_backend() as m, ExitStack() as stack:
-            stack.enter_context(patch.object(cuda, "memset_d8"))
-            stack.enter_context(patch.object(cuda, "memset_d8_async"))
-            stack.enter_context(patch.object(cuda, "memcpy_dtoh",
-                                             side_effect=lambda out, src: out.fill(0)))
-            backend = build(m)
-            b = backend._level_boundaries[1]
-            self.assertIsNotNone(b.window_integral)
-            with self.assertRaises(RuntimeError):
-                backend.start_exchange_window()  # not initialized
-            arrays = [np.full(level.shape, 1 / 9, np.float32) for level in backend._levels]
-            backend.initialize(*arrays)
-            with self.assertRaisesRegex(RuntimeError, "no valid exchange window"):
-                backend.read_exchange_window(0)
-            backend.step(1)
-            self.assertEqual(len(accumulations(m)), 2)  # closed window: interval ledger only
-            backend.start_exchange_window()
-            with self.assertRaisesRegex(RuntimeError, "at least one completed"):
-                backend.read_exchange_window(0)
-            m["calls"].clear()
-            backend.step(2)
-            calls = accumulations(m)
-            self.assertEqual(len(calls), 8)  # two fine hops x two ledgers x two base steps
-            self.assertEqual({id(c[1][1]) for c in calls},
-                             {id(b.interval_integral), id(b.window_integral)})
-            out = backend.read_exchange_window(0)
-            self.assertEqual((out["time_start"], out["time_end"], out["sample_count"]), (1., 3, 4))
-            self.assertEqual(backend.read_exchange_window(0)["time_end"], 3)  # non-destructive
-            backend.initialize(*arrays)  # invalidates
-            with self.assertRaisesRegex(RuntimeError, "no valid exchange window"):
-                backend.read_exchange_window(0)
-            backend.start_exchange_window()
-            with patch.object(backend, "_hop", side_effect=RuntimeError("injected")):
-                with self.assertRaises(RuntimeError):
-                    backend.step(1)
-            self.assertFalse(backend._window_valid)
-            with self.assertRaises(RuntimeError):
-                backend.read_exchange_window(0)  # failed status
-
-    def test_disabled_default_has_no_window_cost(self):
-        with mocked_backend() as m, ExitStack() as stack:
-            stack.enter_context(patch.object(cuda, "memset_d8_async"))
-            backend = build(m, window=False)
-            self.assertIsNone(backend._level_boundaries[1].window_integral)
-            backend.initialize(*[np.full(l.shape, 1 / 9, np.float32) for l in backend._levels])
-            backend.step(1)
-            self.assertEqual(len(accumulations(m)), 2)
-            with self.assertRaisesRegex(RuntimeError, "disabled"):
-                backend.start_exchange_window()
-
-
-class ExchangeWindowGPU(unittest.TestCase):
-    def test_window_matches_summed_base_reads_and_populations_unchanged(self):
-        from test_raw_exchange_gpu import BOUNDS as RB, CFG, circle as rc, jet, state
-        from CelerisLab.cuda.context import CudaContext
-        with CudaContext(0) as ctx:
-            kw = dict(context=ctx, fine_block=(16, 20), fine_objects=[rc()], jets=[jet()],
-                      observe_raw_exchange=True)
-            with FixedPatchStepper(CFG, RB, observe_window_exchange=True, **kw) as windowed, \
-                 FixedPatchStepper(CFG, RB, **kw) as plain:
-                arrays = [state(level.shape) for level in windowed._levels]
-                windowed.initialize(*arrays)
-                plain.initialize(*arrays)
-                windowed.step(2)
-                plain.step(2)
-                windowed.start_exchange_window()
-                b = windowed._level_boundaries[1]
-                count = len(b.tables["cell"])
-                factors = np.array([.25, .25, .125, .25])  # h*dt, h*h*dt, h*h for level-1 h=.5
-                scale = np.zeros(4)
-                substeps = 0
-                kernel = windowed._levels[1].kernel
-
-                def audited(src, dst, *args, **kw):
-                    nonlocal scale, substeps
-                    windowed._stream.synchronize()  # BFL and both accumulations are complete
-                    raw = np.empty((count, 4), np.float32)
-                    cuda.memcpy_dtoh(raw, b.last_raw)
-                    scale = scale + (np.abs(raw.astype(np.float64)) * factors).sum(axis=0)
-                    substeps += 1
-                    kernel(src, dst, *args, **kw)
-                windowed._levels[1].kernel = audited
-                keys = ("impulse", "angular_impulse", "mass_into_fluid")
-                summed = {part: [0., 0., 0., 0.] for part in ("total", "wall", "aperture")}
-                steps = 0
-                for speed in (0., .002, .002, -.001, 0., 0.):  # amplitude updates stay in-window
-                    windowed.set_jet_amplitude(0, speed)
-                    plain.set_jet_amplitude(0, speed)
-                    windowed.step(1)
-                    plain.step(1)
-                    steps += 1
-                    obs = windowed.read_raw_exchange(0)
-                    for part in summed:
-                        o = obs[part]
-                        summed[part] = [summed[part][0] + o["impulse"][0], summed[part][1] + o["impulse"][1],
-                                        summed[part][2] + o["angular_impulse"],
-                                        summed[part][3] + o["mass_into_fluid"]]
-                    for a, e in zip(windowed._download_raw().values, plain._download_raw().values):
-                        same_bits(self, a, e)
-                out = windowed.read_exchange_window(0)
-                self.assertEqual((out["time_end"] - out["time_start"], out["sample_count"]),
-                                 (steps, 2 * steps))
-                self.assertEqual(substeps, 2 * steps)
-                bound = 4 * (count * substeps) * EPS * scale + 1e-300
-                for part in summed:
-                    o = out[part]
-                    got = np.array([o["impulse"][0], o["impulse"][1], o["angular_impulse"],
-                                    o["mass_into_fluid"]])
-                    diff = np.abs(got - np.array(summed[part]))
-                    self.assertTrue((diff <= bound).all(), f"{part}: {diff} > {bound}")
-                    np.testing.assert_array_equal(o["force"], o["impulse"] / steps)
-                again = windowed.read_exchange_window(0)
-                np.testing.assert_array_equal(again["total"]["impulse"], out["total"]["impulse"])
-                windowed.initialize(*arrays)
-                with self.assertRaises(RuntimeError):
-                    windowed.read_exchange_window(0)
-
-
-def audit_substeps(stepper, b, count, record):
-    """Wrap the level-1 step kernel: after BFL and accumulation, add |substep terms| to record."""
-    factors = np.array([.25, .25, .125, .25])
-    kernel = stepper._levels[1].kernel
-
-    def audited(src, dst, *args, **kw):
-        stepper._stream.synchronize()
-        raw = np.empty((count, 4), np.float32)
-        cuda.memcpy_dtoh(raw, b.last_raw)
-        record["scale"] = record["scale"] + (np.abs(raw.astype(np.float64)) * factors).sum(axis=0)
-        record["substeps"] += 1
-        kernel(src, dst, *args, **kw)
-    stepper._levels[1].kernel = audited
-
-
-def components(obs):
-    o = obs["total"]
-    return np.array([o["impulse"][0], o["impulse"][1], o["angular_impulse"], o["mass_into_fluid"]])
-
-
-class ExchangeWindowShiftedMRTGPU(unittest.TestCase):
-    """Shifted MRT, all-blocked, stationary body, NO Jet (scoped separately from SRT/Jet)."""
-
-    def test_window_step0_reset_and_split_step(self):
-        from test_raw_exchange_gpu import BOUNDS as RB, circle as rc, state
-        from CelerisLab.config import LBMConfig
-        from CelerisLab.cuda.context import CudaContext
-        cfg = LBMConfig(nx=32, ny=24, viscosity=.1, collision="MRT", ddf_shifting=True)
-        with CudaContext(0) as ctx:
-            kw = dict(context=ctx, base_block=(12, 8), fine_block=(16, 20), fine_objects=[rc()],
-                      observe_raw_exchange=True)
-            with FixedPatchStepper(cfg, RB, observe_window_exchange=True, **kw) as windowed, \
-                 FixedPatchStepper(cfg, RB, observe_window_exchange=True, **kw) as split, \
-                 FixedPatchStepper(cfg, RB, **kw) as plain:
-                arrays = [state(level.shape) for level in windowed._levels]
-                for run in (windowed, split, plain):
-                    run.initialize(*arrays)
-                    run.step(2)
-                    if run is not plain:
-                        run.start_exchange_window()
-                b = windowed._level_boundaries[1]
-                count = len(b.tables["cell"])
-                record = dict(scale=np.zeros(4), substeps=0)
-                audit_substeps(windowed, b, count, record)
-                steps, summed = 5, np.zeros(4)
-                for _ in range(steps):
-                    windowed.step(1)
-                    plain.step(1)
-                    summed += components(windowed.read_raw_exchange(0))
-                    for a, e in zip(windowed._download_raw().values, plain._download_raw().values):
-                        same_bits(self, a, e)
-                split.step(steps)  # one call: same ledger arithmetic as five step(1) calls
-                for a, e in zip(windowed._download_raw().values, split._download_raw().values):
-                    same_bits(self, a, e)
-                rows = [np.empty((count, 4), np.float64) for _ in range(2)]
-                cuda.memcpy_dtoh(rows[0], b.window_integral)
-                cuda.memcpy_dtoh(rows[1], split._level_boundaries[1].window_integral)
-                np.testing.assert_array_equal(rows[0].view(np.uint64), rows[1].view(np.uint64))
-
-                out = windowed.read_exchange_window(0)
-                self.assertEqual(record["substeps"], 2 * steps)
-                self.assertEqual((out["time_end"] - out["time_start"], out["sample_count"]),
-                                 (steps, 2 * steps))
-                bound = 4 * (count * record["substeps"]) * EPS * record["scale"] + 1e-300
-                diff = np.abs(components(out) - summed)
-                self.assertTrue((diff <= bound).all(), f"{diff} > {bound}")
-                np.testing.assert_array_equal(split.read_exchange_window(0)["total"]["impulse"],
-                                              out["total"]["impulse"])
-
-                windowed.step(0)  # no interval: window and its duration unchanged
-                again = windowed.read_exchange_window(0)
-                self.assertEqual(again["time_end"], out["time_end"])
-                np.testing.assert_array_equal(again["total"]["impulse"], out["total"]["impulse"])
-
-                windowed.start_exchange_window()  # reset after a window
-                with self.assertRaisesRegex(RuntimeError, "at least one completed"):
-                    windowed.read_exchange_window(0)
-                record.update(scale=np.zeros(4), substeps=0)
-                windowed.step(1)
-                single = components(windowed.read_raw_exchange(0))
-                reset = windowed.read_exchange_window(0)
-                self.assertEqual(reset["time_end"] - reset["time_start"], 1)
-                bound = 4 * (count * record["substeps"]) * EPS * record["scale"] + 1e-300
-                self.assertTrue((np.abs(components(reset) - single) <= bound).all())
-
-
-if __name__ == "__main__": unittest.main()

tests/validation/multigrid/test_refinement_mrt_gpu.py

@@ -1,95 +0,0 @@
-"""MRT reuse GPU gates. Caller owns GPU admission (CUDA_VISIBLE_DEVICES).
-
-Run: python -m unittest discover -s tests/validation/multigrid -p test_refinement_mrt_gpu.py
-Parity compares the blocked MRT channel root with uniform MRT OneStep: the existing
-pressure-NEQ outlet branch differs by collision model, so SRT is never the reference.
-AMR checks are finite-evolution/split-invariance smoke tests, not benchmark validation.
-"""
-from dataclasses import replace
-import unittest
-import numpy as np
-
-from CelerisLab.config import LBMConfig
-from CelerisLab.cuda.context import CudaContext
-from CelerisLab.lbm.population_storage import _encode_physical
-from CelerisLab.lbm.refinement_stepper import FixedPatchStepper
-from test_channel_root_gpu import run_root, state
-from test_refinement_blocked_base import raw, exact
-
-
-class RefinementMRTGPU(unittest.TestCase):
-    def test_uniform_matched_mrt_root(self):
-        with CudaContext(0) as context:
-            for shifted in (False, True):
-                for profile in ("uniform", "parabolic"):
-                    cfg = LBMConfig(nx=24, ny=20, viscosity=.1, velocity=.025, collision="MRT",
-                                    ddf_shifting=shifted, inlet_profile=profile)
-                    initial = _encode_physical(state(cfg.ny, cfg.nx), shifted)
-                    expected = run_root(cfg, context, initial)
-                    self.assertTrue(np.isfinite(expected).all())
-                    for block in ((20, 24), (5, 6), (4, 1)):
-                        np.testing.assert_array_equal(run_root(cfg, context, initial, block), expected)
-
-    def test_amr_mrt_smoke(self):
-        from CelerisLab.body.geometry.circle import CircleGeometry
-        from CelerisLab.body.objects import SimObject
-        center = (24., 16.)
-        body = SimObject(0, geometry=CircleGeometry(*center, 2.15), center=center, radius=2.15)
-        with CudaContext(0) as context:
-            for boundary in ("periodic", "channel"):
-                for shifted in (False, True):
-                    cfg = LBMConfig(nx=48, ny=32, viscosity=.1, velocity=.015 if boundary == "channel" else 0.,
-                                    collision="MRT", ddf_shifting=shifted)
-                    reference = None
-                    for block in ((32, 48), (8, 8), (4, 1)):
-                        with FixedPatchStepper(cfg, (8, 6, 40, 26), context=context, coarse_boundary=boundary,
-                                               base_block=block, fine_block=(8, 8), fine_objects=(body,)) as backend:
-                            backend.initialize(*[state(*level.shape[1:]) for level in backend._levels])
-                            backend.step(8)
-                            raw = backend._download_raw()
-                            for a, mask in zip(raw.values, backend._state):
-                                self.assertTrue(np.isfinite(a[:, mask]).all())
-                            if reference is None: reference = raw.values
-                            else:
-                                for a, b in zip(reference, raw.values): np.testing.assert_array_equal(a, b)
-
-    def test_dense_versus_blocked_mrt_two_level(self):
-        """Unshifted MRT: all-dense PatchCoarseStep/PatchFineStep vs mixed/all-blocked storage."""
-        from test_refinement_blocked_base import BASE_BLOCKS, FINE_BLOCK
-        from test_refinement_blocked_fine import NX, NY, BOUNDS
-        import test_refinement_blocked_fine as fixture
-        cfg = LBMConfig(nx=NX, ny=NY, viscosity=.1, collision="MRT")
-        with CudaContext(0) as context:
-            results = {}
-            layouts = ((None, None), *((base, FINE_BLOCK) for base in (None, *BASE_BLOCKS)))
-            for base_block, fine_block in layouts:
-                with FixedPatchStepper(cfg, BOUNDS, context=context, fine_block=fine_block,
-                                       base_block=base_block) as backend:
-                    backend.initialize(*[fixture.state(*level.shape[1:], seed) for seed, level in enumerate(backend._levels)])
-                    backend.step(4)
-                    results[base_block, fine_block] = raw(backend)
-            for layout in layouts[1:]:
-                for level, (a, b) in enumerate(zip(results[layout], results[None, None])):
-                    exact(self, a, b, f"layout={layout} level={level}")
-
-    def test_shifted_all_blocked_three_level_mrt_smoke(self):
-        """Per-level shear rate omega_l = 1/(3*2**l*nu + 1/2); finite ACTIVE leaves."""
-        cfg = LBMConfig(nx=16, ny=16, viscosity=.1, collision="MRT", ddf_shifting=True)
-        kw = dict(fine_block=(4, 4), base_block=(4, 4), child=(8, 8, 16, 16), child_block=(4, 4))
-        with CudaContext(0) as context:
-            with FixedPatchStepper(cfg, (4, 4, 12, 12), context=context, **kw) as backend:
-                self.assertEqual(len(backend._level_cfgs), 3)
-                for level, level_cfg in enumerate(backend._level_cfgs):
-                    checked = replace(level_cfg)
-                    checked.validate()  # omega is derived only by validate()
-                    self.assertEqual(checked.collision, "MRT")
-                    self.assertTrue(checked.ddf_shifting)
-                    self.assertTrue(np.isclose(checked.omega, 1 / (3 * 2**level * .1 + .5), rtol=1e-14))
-                backend.initialize(*[state(*level.shape[1:]) for level in backend._levels])
-                backend.step(4)
-                values = backend._download_raw().values
-                for a, mask in zip(values, backend._state):
-                    self.assertTrue(np.isfinite(a[:, mask]).all())
-
-
-if __name__ == "__main__": unittest.main()

tests/validation/run_refined_dfg.py

@@ -1,4 +1,4 @@
-"""Frozen matched SRT/MRT DFG comparison. GPU execution requires explicit root admission."""
+"""Frozen matched SRT DFG comparison. GPU execution requires explicit root admission."""
 
 import argparse
 import csv
@@ -39,21 +39,20 @@ def helpers(source):
     return h, periodic
 
 
-def config(h, diameter, collision="SRT"):
-    cfg, body, p = h.make_config(diameter, SPEED, collision, "neq_extrap", "zou_he_local")
+def config(h, diameter):
+    cfg, body, p = h.make_config(diameter, SPEED, "SRT", "neq_extrap", "zou_he_local")
     cfg["method"]["outlet"]["srt_neq_damp"] = 0.5
     return cfg, body, p
 
 
-def plan(h, collision="SRT"):
-    _, _, c = config(h, 40, collision)
-    _, _, f = config(h, 80, collision)
+def plan(h):
+    _, _, c = config(h, 40)
+    _, _, f = config(h, 80)
     x0, y0, x1, y1 = BOUNDS
     fine_active = 4 * (x1 - x0) * (y1 - y0)
     coarse_uncovered = c["nx"] * c["ny"] - fine_active // 4
     return dict(
         status="prepared_not_run",
-        collision=collision,
         root_gpu_gates_required=True,
         root=c,
         uniform=f,
@@ -83,11 +82,7 @@ def plan(h, collision="SRT"):
         / (2 * f["nx"] * f["ny"]),
         cost_caveat="Geometry-only estimates include ghosts/solids; exclude block halos, transfers, observation and launch overhead. Not measured speedup.",
         sampling_offset="For origin (38,22), fine physical x=(j+75.5)*dx80 versus uniform i*dx80: half-fine-cell x offset. Fine physical y=(k+42.5)*dx80 equals uniform (l-.5)*dx80 at l=k+43: y samples align. Body, wall and source planes coincide.",
-        outlet=(
-            "SRT pressure NEQ, all nine fneq damped by .5, no backflow clamp; noncanonical DFG outlet"
-            if collision == "SRT" else
-            "MRT pressure NEQ, unknowns q2/6/8 extrapolated; no backflow clamp; noncanonical DFG outlet"
-        ),
+        outlet="SRT pressure NEQ, all nine fneq damped by .5, no backflow clamp; noncanonical DFG outlet",
         modes={"pilot_tstar": 5.0, "full_tstar": 300.0},
         observation_dense_tstar=0.02,
     )
@@ -125,7 +120,7 @@ def initial_state(shape, origin, spacing, height=164.0, speed=SPEED, root=False)
     return w * (1 + 3 * cu + 4.5 * cu * cu - 1.5 * velocity * velocity)
 
 
-def host_geometry(source, h, collision="SRT"):
+def host_geometry(source, h):
     """Production donor/transfer and complete cut-link checks, without CUDA."""
     from CelerisLab.config import load_lbm_config
     from CelerisLab.lbm.refinement import FixedPatch2D, prepare_fine_boundary
@@ -138,7 +133,7 @@ def host_geometry(source, h, collision="SRT"):
     from CelerisLab.body.geometry.circle import CircleGeometry
     from CelerisLab.body.objects import SimObject
 
-    cfgdict, _, _ = config(h, 40, collision)
+    cfgdict, _, _ = config(h, 40)
     with TemporaryDirectory() as tmp:
         p = Path(tmp) / "cfg.json"
         p.write_text(json.dumps(cfgdict))
@@ -156,11 +151,8 @@ def host_geometry(source, h, collision="SRT"):
     return cfg, pair, body, host
 
 
-def verify_source(source, collision="SRT"):
-    if collision not in ("SRT", "MRT"):
-        raise ValueError("Matched collision must be SRT or MRT")
-    name = "source_manifest.json" if collision == "SRT" else "source_manifest_mrt.json"
-    expected = json.loads((HERE / "data/refined_dfg" / name).read_text())
+def verify_source(source):
+    expected = json.loads((HERE / "data/refined_dfg/source_manifest.json").read_text())
     for name, digest in expected["sha256"].items():
         if hashlib.sha256((source / name).read_bytes()).hexdigest() != digest:
             raise RuntimeError("Source mismatch: " + name)
@@ -175,7 +167,7 @@ def run_case(a, h, periodic, case):
     from contextlib import ExitStack
 
     refined = case == "refined"
-    cfgdict, bodydict, p = config(h, 40 if refined else 80, a.collision)
+    cfgdict, bodydict, p = config(h, 40 if refined else 80)
     cap = 5.0 if a.mode == "pilot" else 300.0
     max_steps = math.ceil(cap * p["diameter"] / SPEED)
     rows = []
@@ -187,7 +179,7 @@ def run_case(a, h, periodic, case):
     dest.mkdir()
     with ExitStack() as stack:
         if refined:
-            cfg, pair, body, host = host_geometry(a.source, h, a.collision)
+            cfg, pair, body, host = host_geometry(a.source, h)
             context = stack.enter_context(CudaContext(0))
             backend = stack.enter_context(
                 FixedPatchStepper(
@@ -344,8 +336,6 @@ def run_case(a, h, periodic, case):
                 if len(rows) == 1:
                     ready = dict(
                         case=case,
-                        collision=a.collision,
-                        **a.provenance,
                         mode=a.mode,
                         step=begin,
                         tstar=row["tstar"],
@@ -358,8 +348,6 @@ def run_case(a, h, periodic, case):
                     print("READY " + json.dumps(ready, allow_nan=False), flush=True)
     result = dict(
         case=case,
-        collision=a.collision,
-        **a.provenance,
         mode=a.mode,
         history=rows,
         healthy=bool(healthy),
@@ -428,14 +416,12 @@ def check_deadline(deadline):
         )
 
 
-def verify_pilot(path, manifest, collision="SRT"):
+def verify_pilot(path, manifest):
     if path is None:
         raise ValueError(
             "Full comparison requires --pilot-results from a completed matched pilot"
         )
     previous = read_finite_json(path / "plan.json")
-    if previous.get("collision") != collision:
-        raise ValueError("Pilot collision differs")
     if previous["source_manifest"] != manifest or previous["bounds_root_edge"] != list(
         BOUNDS
     ):
@@ -446,8 +432,7 @@ def verify_pilot(path, manifest, collision="SRT"):
     for case, diameter in (("uniform", 80), ("refined", 40)):
         summary = read_finite_json(path / case / "summary.json")
         if (
-            summary.get("collision") != collision
-            or summary.get("case") != case
+            summary.get("case") != case
             or summary.get("mode") != "pilot"
             or summary.get("status") != "pilot_complete"
             or summary.get("healthy") is not True
@@ -498,8 +483,7 @@ def verify_pilot(path, manifest, collision="SRT"):
                 raise ValueError("Unhealthy pilot observations")
         ready = read_finite_json(path / case / "ready.json")
         if (
-            ready.get("collision") != collision
-            or ready.get("case") != case
+            ready.get("case") != case
             or ready.get("mode") != "pilot"
             or ready.get("step") != interval
             or ready.get("runner_sha256") != runner_hash()
@@ -523,7 +507,6 @@ def verify_pilot(path, manifest, collision="SRT"):
 
 def main():
     parser = argparse.ArgumentParser(description=__doc__)
-    parser.add_argument("--collision", choices=["SRT", "MRT"], default="SRT")
     parser.add_argument("--source", type=Path, default=DEFAULT_SOURCE)
     parser.add_argument("--output", type=Path, required=True)
     parser.add_argument("--mode", choices=["plan", "pilot", "full"], default="plan")
@@ -536,15 +519,9 @@ def main():
     )
     a = parser.parse_args()
     a.source = a.source.resolve()
-    manifest = verify_source(a.source, a.collision)
+    manifest = verify_source(a.source)
     h, periodic = helpers(a.source)
-    from source_provenance import checkout_provenance
-
-    a.provenance = checkout_provenance(a.source)
-    calibration = (
-        verify_pilot(a.pilot_results, manifest, a.collision)
-        if a.mode == "full" else None
-    )
+    calibration = verify_pilot(a.pilot_results, manifest) if a.mode == "full" else None
     if a.mode != "plan" and (
         a.max_wall_seconds is None
         or not math.isfinite(a.max_wall_seconds)
@@ -559,17 +536,16 @@ def main():
     if a.output.exists() and any(a.output.iterdir()):
         raise ValueError("Output must be empty/new")
     a.output.mkdir(parents=True, exist_ok=True)
-    specification = plan(h, a.collision)
+    specification = plan(h)
     specification.update(
         source_manifest=manifest,
-        **a.provenance,
         gates=periodic.GATES,
         reference_gates=periodic.REFERENCE_GATES,
         runner_sha256=runner_hash(),
         wall_time_budget_seconds=budget,
         full_pilot_calibration_seconds=calibration,
     )
-    host_geometry(a.source, h, a.collision)
+    host_geometry(a.source, h)
     (a.output / "plan.json").write_text(json.dumps(specification, indent=2))
     if a.mode == "plan":
         return 0
@@ -585,8 +561,6 @@ def main():
         except TimeoutError as exc:
             failure = dict(
                 status="wall_time_limit",
-                collision=a.collision,
-                **a.provenance,
                 case=case,
                 matched_case_pass=False,
                 error=str(exc),
@@ -600,8 +574,6 @@ def main():
         if not result["healthy"]:
             break
     comparison = dict(
-        collision=a.collision,
-        **a.provenance,
         status="pilot_only" if a.mode == "pilot" else "incomplete",
         matched_case_pass=False,
     )

tests/validation/time_refined_dfg.py

@@ -1,326 +0,0 @@
-"""Measurement-only wall timing for the matched MRT refined DFG case. No numerical edits.
-
-Variants over EQUAL simulated duration (one refined base step = two uniform D80 steps):
-  A  refined: step(1) + read_raw_exchange per base step  -- runner-like force-read workload
-  B  refined: step(1) only, no host reads        -- timing-only, no force history
-  C  refined: one step(N) call                   -- timing-only; ledger keeps final base interval only
-  E  uniform: sim.run(<=100) + read_force                -- runner-like force-read workload
-  E' uniform: one sim.run(2N) call                -- timing-only; at most a whole-window force
-                                                    average (different summation order), no history
-A/E read forces but discard them: no retained force history, no interval aggregation/validation,
-and no macro/probe/CSV cost, so they are not full benchmark throughput.
-observe_raw_exchange stays True for A/B/C: B/C omit host reads only.
-Status lines: CONSTRUCTED = backend/simulation built (JIT done); WARM_READY = first warm-up and
-health check passed for that case.
-Parity compares A/B/C with each other and E/E' with each other, never uniform with refined.
-A-B and B-C are measured comparative differences, not exact causal decompositions.
-Each repeat starts from the same fresh initial state with the same warm-up; construction,
-compilation, parity and health checks are outside timed regions. The actual stepping stream is
-synchronized explicitly immediately before the timer starts and after the timed loop. Wall time
-(perf_counter) is the only timing source; no CUDA-event span is reported as kernel time. An outer
---max-wall-seconds deadline is checked between variants and inside per-step loops.
-"""
-
-import argparse
-import json
-import math
-import os
-from pathlib import Path
-import statistics
-import sys
-import time
-from tempfile import TemporaryDirectory
-
-import numpy as np
-
-HERE = Path(__file__).resolve().parent
-sys.path.insert(0, str(HERE))
-import run_refined_dfg as r  # noqa: E402  (published runner: same setup functions)
-
-VARIANTS = {
-    "A": dict(case="refined", force_history_valid=False, force_reads=True,
-              force_note="runner-like force-read workload; values discarded, no aggregation"),
-    "B": dict(case="refined", force_history_valid=False, timing_only=True,
-              force_note="no host reads"),
-    "C": dict(case="refined", force_history_valid=False, timing_only=True,
-              force_note="raw ledger retains only the final base interval"),
-    "E": dict(case="uniform", force_history_valid=False, force_reads=True,
-              force_note="runner-like force-read workload; values discarded, no aggregation"),
-    "E'": dict(case="uniform", force_history_valid=False, timing_only=True,
-               force_note="at most a whole-window accumulated average; different summation order"),
-}
-
-
-def schedule(n_base, warmup_base):
-    """Steps per case for equal simulated duration (refined dt_root = 2 dt_uniform)."""
-    if n_base <= 0 or warmup_base < 0:
-        raise ValueError("n_base must be positive and warmup_base nonnegative")
-    return dict(refined=(warmup_base, n_base), uniform=(2 * warmup_base, 2 * n_base),
-                tstar_window=n_base * r.SPEED / 40.0)
-
-
-# Existing run_refined_dfg safety limits (rho in [.5, 1.5], sampled max Mach <= .2).
-RHO_LIMITS, MAX_MACH = (0.5, 1.5), 0.2
-
-
-def same_state(reference, values):
-    """Bitwise populations and identical NaN masks; returns a short description or None.
-
-    Matching NaN is accepted only as a storage mask (inactive/ghost/solid slots); physical
-    leaf health is checked separately. Any infinity in either state is a mismatch.
-    """
-    reference, values = list(reference), list(values)
-    if len(reference) != len(values):
-        return f"level count {len(reference)} != {len(values)}"
-    for level, (a, b) in enumerate(zip(reference, values)):
-        a, b = np.asarray(a), np.asarray(b)
-        if a.shape != b.shape:
-            return f"level {level}: shape {a.shape} != {b.shape}"
-        if np.isinf(a).any() or np.isinf(b).any():
-            return f"level {level}: infinite population"
-        if not np.array_equal(np.isnan(a), np.isnan(b)):
-            return f"level {level}: NaN mask differs"
-        finite = np.isfinite(a)
-        if a.dtype != b.dtype or not np.array_equal(a[finite].view(np.uint8), b[finite].view(np.uint8)):
-            return f"level {level}: finite bits differ"
-    return None
-
-
-def uniform_populations_finite(ddf, fluid):
-    """Simulation.get_ddf() may be flat (9*ny*nx); view it as (Q, cells) before masking."""
-    ddf, fluid = np.asarray(ddf), np.asarray(fluid, bool).ravel()
-    if fluid.size == 0 or ddf.size % fluid.size:
-        raise RuntimeError(f"DDF size {ddf.size} incompatible with {fluid.size} cells")
-    return bool(np.isfinite(ddf.reshape(ddf.size // fluid.size, fluid.size)[:, fluid]).all())
-
-
-def physical_health(fields):
-    """fields: (rho, ux, uy) arrays already restricted to physical leaves/fluid."""
-    if not fields or any(not np.isfinite(v).all() or v.size == 0 for f in fields for v in f):
-        raise RuntimeError("nonfinite or empty physical macroscopic field")
-    rho_min = float(min(f[0].min() for f in fields))
-    rho_max = float(max(f[0].max() for f in fields))
-    max_mach = float(max(np.sqrt(3 * (f[1] ** 2 + f[2] ** 2)).max() for f in fields))
-    if not (RHO_LIMITS[0] <= rho_min <= rho_max <= RHO_LIMITS[1] and max_mach <= MAX_MACH):
-        raise RuntimeError(f"health limits violated: rho [{rho_min}, {rho_max}], Mach {max_mach}")
-    return dict(rho_min=rho_min, rho_max=rho_max, max_mach=max_mach)
-
-
-def refined_health(backend, masks):
-    arrays = backend.download()  # physical FP64 populations; non-leaves NaN by contract
-    if any(not np.isfinite(g[:, m]).all() for g, m in zip(arrays, masks)):
-        raise RuntimeError("nonfinite physical leaf population")
-    return physical_health([tuple(v[m] for v in r.macros(g)) for g, m in zip(arrays, masks)])
-
-
-def uniform_health(sim, fluid):
-    m = sim.get_macroscopic()
-    return physical_health([tuple(np.asarray(m[k], np.float64).reshape(fluid.shape)[fluid]
-                                  for k in ("rho", "ux", "uy"))])
-
-
-def check_deadline(deadline):
-    if time.monotonic() >= deadline:
-        raise TimeoutError("timing harness exceeded --max-wall-seconds")
-
-
-def sync_refined(backend):
-    with backend.ctx.activate():
-        backend._stream.synchronize()
-
-
-def sync_uniform(sim):
-    with sim.ctx.activate():
-        sim.stream.synchronize()
-
-
-def refined_loop(backend, variant, n, deadline):
-    if variant == "C":
-        backend.step(n)
-        return
-    for i in range(n):
-        backend.step(1)
-        if variant == "A":
-            backend.read_raw_exchange(0, level=1, window="last_base_step")
-        if i % 100 == 99:
-            check_deadline(deadline)
-
-
-def uniform_loop(sim, variant, n, deadline):
-    if variant == "E'":
-        sim.run(n)
-        return
-    done = 0
-    while done < n:
-        batch = min(100, n - done)
-        sim.run(batch)
-        sim.read_force(0)
-        done += batch
-        check_deadline(deadline)
-
-
-def time_refined(a, h, sched):
-    from contextlib import ExitStack
-    from CelerisLab.cuda.context import CudaContext
-    from CelerisLab.lbm.refinement_stepper import FixedPatchStepper
-    from CelerisLab.lbm.channel import channel_masks
-    from CelerisLab.lbm.refinement import ACTIVE
-    from CelerisLab.lbm.descriptors import SOLID
-
-    warm, n = sched["refined"]
-    rows, reference = [], {}
-    with ExitStack() as stack:
-        cfg, pair, body, host = r.host_geometry(a.source, h, "MRT")
-        context = stack.enter_context(CudaContext(0))
-        backend = stack.enter_context(FixedPatchStepper(
-            cfg, r.BOUNDS, context=context, coarse_boundary="channel", base_block=r.BASE_BLOCK,
-            fine_block=r.FINE_BLOCK, fine_objects=(body,), observe_raw_exchange=True))
-        masks = [channel_masks(pair.coarse_shape)[0] & ~pair.covered,  # as run_refined_dfg
-                 (pair.fine_kind == ACTIVE) & ((host.flags.reshape(pair.fine_shape) & SOLID) == 0)]
-        fresh = (r.initial_state(pair.coarse_shape, (0.0, 0.0), 1.0, root=True),
-                 r.initial_state(pair.fine_shape, pair.fine_origin, 0.5))
-        print(json.dumps(dict(status="CONSTRUCTED", case="refined")), flush=True)
-        for repeat in range(a.repeats):
-            for variant in ("A", "B", "C"):
-                check_deadline(a.deadline)
-                backend.initialize(*fresh)  # resets step count; same fresh state every time
-                refined_loop(backend, variant, warm, a.deadline)
-                warm_health = refined_health(backend, masks)  # untimed
-                if repeat == 0 and variant == "A":
-                    print(json.dumps(dict(status="WARM_READY", case="refined")), flush=True)
-                sync_refined(backend)
-                start = time.perf_counter()
-                refined_loop(backend, variant, n, a.deadline)
-                sync_refined(backend)
-                seconds = time.perf_counter() - start
-                end_health = refined_health(backend, masks)  # untimed
-                values = [np.array(v, copy=True) for v in backend._download_raw().values]
-                if not all(np.isfinite(v[:, m]).all() for v, m in zip(values, backend._state)):
-                    raise RuntimeError(f"refined {variant} repeat {repeat}: nonfinite leaf populations")
-                mismatch = None
-                if repeat == 0 and variant == "A":
-                    reference["A"] = values
-                else:
-                    mismatch = same_state(reference["A"], values)
-                rows.append(dict(variant=variant, repeat=repeat, seconds=seconds,
-                                 base_steps=n, step_count=backend.step_count,
-                                 health_after_warmup=warm_health, health_after_window=end_health,
-                                 parity_vs_A=mismatch or "identical", **VARIANTS[variant]))
-                if mismatch:
-                    raise RuntimeError(f"refined {variant} repeat {repeat}: {mismatch}")
-    return rows
-
-
-def time_uniform(a, h, sched):
-    from CelerisLab.simulation import Simulation
-    from CelerisLab.lbm.descriptors import FLUID
-
-    warm, n = sched["uniform"]
-    rows, reference = [], {}
-    cfgdict, bodydict, params = r.config(h, 80, "MRT")
-    with TemporaryDirectory() as tmp:
-        tmp = Path(tmp)
-        (tmp / "lbm.json").write_text(json.dumps(cfgdict))
-        (tmp / "body.json").write_text(json.dumps(bodydict))
-        with Simulation(str(tmp / "lbm.json"), str(tmp / "body.json"), device_id=0) as sim:
-            sim.initialize()
-            sim.snapshot()  # fresh state; restore keeps clock and streaming parity
-            fluid = (sim.get_flags() & FLUID) != 0
-            ny, nx = params["ny"], params["nx"]
-            fluid = fluid.reshape(ny, nx)
-            print(json.dumps(dict(status="CONSTRUCTED", case="uniform")), flush=True)
-            for repeat in range(a.repeats):
-                for variant in ("E", "E'"):
-                    check_deadline(a.deadline)
-                    sim.restore()
-                    if sim.stepper.step_count % 2:
-                        raise RuntimeError("uniform restore parity changed between variants")
-                    uniform_loop(sim, variant, warm, a.deadline)
-                    warm_health = uniform_health(sim, fluid)  # untimed
-                    if repeat == 0 and variant == "E":
-                        print(json.dumps(dict(status="WARM_READY", case="uniform")), flush=True)
-                    sync_uniform(sim)
-                    start = time.perf_counter()
-                    uniform_loop(sim, variant, n, a.deadline)
-                    sync_uniform(sim)
-                    seconds = time.perf_counter() - start
-                    end_health = uniform_health(sim, fluid)  # untimed
-                    values = [sim.get_ddf()]
-                    if not uniform_populations_finite(values[0], fluid):
-                        raise RuntimeError(f"uniform {variant} repeat {repeat}: nonfinite fluid populations")
-                    mismatch = None
-                    if repeat == 0 and variant == "E":
-                        reference["E"] = values
-                    else:
-                        mismatch = same_state(reference["E"], values)
-                    rows.append(dict(variant=variant, repeat=repeat, seconds=seconds,
-                                     uniform_steps=n, parity_vs_E=mismatch or "identical",
-                                     health_after_warmup=warm_health, health_after_window=end_health,
-                                     **VARIANTS[variant]))
-                    if mismatch:
-                        raise RuntimeError(f"uniform {variant} repeat {repeat}: {mismatch}")
-    return rows
-
-
-def summarize(rows, tstar_window):
-    summary = {}
-    for variant in VARIANTS:
-        seconds = [row["seconds"] for row in rows if row["variant"] == variant]
-        if seconds:
-            median = statistics.median(seconds)
-            summary[variant] = dict(median_seconds=median, seconds=seconds,
-                                    seconds_per_tstar=median / tstar_window,
-                                    **VARIANTS[variant])
-    if {"A", "B", "C"} <= summary.keys():
-        summary["A_minus_B_seconds"] = summary["A"]["median_seconds"] - summary["B"]["median_seconds"]
-        summary["B_minus_C_seconds"] = summary["B"]["median_seconds"] - summary["C"]["median_seconds"]
-    if {"A", "E"} <= summary.keys():
-        summary["A_over_E"] = summary["A"]["median_seconds"] / summary["E"]["median_seconds"]
-    if {"C", "E'"} <= summary.keys():
-        summary["C_over_Eprime"] = summary["C"]["median_seconds"] / summary["E'"]["median_seconds"]
-    summary["interpretation"] = ("Measured comparative differences under GPU variability; "
-                                 "not exact causal decompositions or performance claims.")
-    return summary
-
-
-def main():
-    p = argparse.ArgumentParser(description=__doc__)
-    p.add_argument("--source", type=Path, default=r.DEFAULT_SOURCE)
-    p.add_argument("--output", type=Path, required=True)
-    p.add_argument("--base-steps", type=int, default=2000)
-    p.add_argument("--warmup-base-steps", type=int, default=200)
-    p.add_argument("--repeats", type=int, default=3)
-    p.add_argument("--max-wall-seconds", type=float, help="Required outer timeout for GPU runs")
-    p.add_argument("--plan", action="store_true")
-    a = p.parse_args()
-    if a.repeats < 1 or a.base_steps > 20000:
-        p.error("repeats must be >= 1 and base-steps <= 20000")
-    a.source = a.source.resolve()
-    manifest = r.verify_source(a.source, "MRT")
-    sched = schedule(a.base_steps, a.warmup_base_steps)
-    plan = dict(collision="MRT", manifest_commit=manifest["commit"], schedule=sched,
-                repeats=a.repeats, variants=VARIANTS, timer="time.perf_counter wall",
-                excluded="construction/JIT, warm-up, state download and parity checks")
-    if a.plan:
-        print(json.dumps(plan, indent=2))
-        return 0
-    if a.max_wall_seconds is None or not math.isfinite(a.max_wall_seconds) or a.max_wall_seconds <= 0:
-        p.error("GPU timing requires a finite positive --max-wall-seconds")
-    a.deadline = time.monotonic() + a.max_wall_seconds
-    if not os.environ.get("CUDA_VISIBLE_DEVICES") or "," in os.environ["CUDA_VISIBLE_DEVICES"]:
-        p.error("Root must select exactly one verified idle GPU via CUDA_VISIBLE_DEVICES")
-    if a.output.exists() and any(a.output.iterdir()):
-        p.error("Output must be empty/new")
-    a.output.mkdir(parents=True, exist_ok=True)
-    h, _ = r.helpers(a.source)
-    rows = time_uniform(a, h, sched) + time_refined(a, h, sched)
-    result = dict(plan=plan, rows=rows, summary=summarize(rows, sched["tstar_window"]))
-    if not all(math.isfinite(row["seconds"]) for row in rows):
-        raise RuntimeError("Nonfinite timing")
-    (a.output / "timing.json").write_text(json.dumps(result, indent=2))
-    print(json.dumps(result["summary"], indent=2), flush=True)
-    return 0
-
-
-if __name__ == "__main__":
-    sys.exit(main())

tests/validation/time_window_dfg.py

@@ -1,183 +0,0 @@
-"""Measurement-only A-versus-window timing for the matched shifted-MRT refined DFG setup.
-
-Candidate source (window ledger) is recorded by checkout revision, dirty flag and file hashes;
-the frozen refined-DFG manifests/results are NOT used or modified (they pin pre-window source).
-Equal simulated duration, same fresh state and warm-up per variant, one observation interval =
-80 root base steps (the runner's dense-phase interval):
-  A   per base step: step(1) + read_raw_exchange, summed per interval (current runner workload)
-  W   per interval: start_exchange_window(); step(80); read_exchange_window()
-  W1  per interval: start_exchange_window(); 80 x step(1); read_exchange_window()
-All variants keep observe_raw_exchange=True; the backend is built once with
-observe_window_exchange=True (a closed window adds no launch). Populations (bitwise) and
-per-interval total impulses are compared OUTSIDE timing; the impulse tolerance is a
-conservative engineering tolerance (see INTERVAL_RTOL); the tighter substep-scaled engineering
-tolerance is exercised by the capability test tests/validation/multigrid/test_exchange_window.py.
-Wall time (perf_counter) with explicit stream synchronization is the only timing source.
-"""
-
-import argparse
-import hashlib
-import json
-import math
-import os
-from pathlib import Path
-import statistics
-import sys
-import time
-
-import numpy as np
-
-HERE = Path(__file__).resolve().parent
-sys.path.insert(0, str(HERE))
-import time_refined_dfg as t  # noqa: E402  (reuses run_refined_dfg setup via t.r)
-
-r = t.r
-INTERVAL = 80
-VARIANTS = ("A", "W", "W1")
-# Interval impulses differ only by FP64 summation order (per link over time vs per step over
-# links). Engineering tolerance: 1e-9 of the interval's summed absolute per-step totals.
-INTERVAL_RTOL = 1e-9
-CANDIDATE_FILES = ("src/CelerisLab/lbm/refinement_stepper.py", "src/CelerisLab/lbm/raw_exchange.py",
-                   "src/CelerisLab/lbm/refinement_tables.py", "src/CelerisLab/lbm/kernels/blocks.cu")
-
-
-def components(obs):
-    o = obs["total"]
-    return np.array([o["impulse"][0], o["impulse"][1], o["angular_impulse"], o["mass_into_fluid"]])
-
-
-def candidate_identity(source):
-    from source_provenance import checkout_provenance
-    return dict(checkout_provenance(source),
-                sha256={f: hashlib.sha256((source / f).read_bytes()).hexdigest()
-                        for f in CANDIDATE_FILES})
-
-
-def run_variant(backend, variant, n_intervals, deadline):
-    """Returns per-interval totals and, for A, per-interval summed |per-step totals|."""
-    totals, scales = [], []
-    for _ in range(n_intervals):
-        if variant == "A":
-            impulse, scale = np.zeros(4), np.zeros(4)
-            for _ in range(INTERVAL):
-                backend.step(1)
-                c = components(backend.read_raw_exchange(0, level=1, window="last_base_step"))
-                impulse += c
-                scale += np.abs(c)
-            totals.append(impulse)
-            scales.append(scale)
-        else:
-            backend.start_exchange_window()
-            if variant == "W":
-                backend.step(INTERVAL)
-            else:
-                for _ in range(INTERVAL):
-                    backend.step(1)
-            totals.append(components(backend.read_exchange_window(0)))
-        t.check_deadline(deadline)
-    return np.array(totals), (np.array(scales) if scales else None)
-
-
-def compare_intervals(reference, scales, totals):
-    """Max violation ratio; <= 1 passes. Scale includes a floor so zero cancels cannot divide."""
-    bound = INTERVAL_RTOL * scales + 1e-300
-    return float(np.max(np.abs(totals - reference) / bound))
-
-
-def main():
-    p = argparse.ArgumentParser(description=__doc__)
-    p.add_argument("--source", type=Path, default=r.DEFAULT_SOURCE)
-    p.add_argument("--output", type=Path, required=True)
-    p.add_argument("--base-steps", type=int, default=2000)
-    p.add_argument("--warmup-base-steps", type=int, default=200)
-    p.add_argument("--repeats", type=int, default=3)
-    p.add_argument("--max-wall-seconds", type=float)
-    p.add_argument("--plan", action="store_true")
-    a = p.parse_args()
-    if a.base_steps <= 0 or a.base_steps % INTERVAL or a.base_steps > 20000 or a.repeats < 1:
-        p.error(f"base-steps must be a positive multiple of {INTERVAL} (<= 20000); repeats >= 1")
-    a.source = a.source.resolve()
-    identity = candidate_identity(a.source)
-    plan = dict(collision="MRT", shifted_storage="as run_refined_dfg MRT config",
-                candidate_source=identity, frozen_manifests_used=False, interval_base_steps=INTERVAL,
-                base_steps=a.base_steps, warmup_base_steps=a.warmup_base_steps, repeats=a.repeats,
-                variants=VARIANTS, tstar_window=a.base_steps * r.SPEED / 40.0,
-                timer="time.perf_counter wall with explicit stream sync",
-                excluded="construction/JIT, warm-up, health, downloads, parity/impulse comparison")
-    if a.plan:
-        print(json.dumps(plan, indent=2))
-        return 0
-    if a.max_wall_seconds is None or not math.isfinite(a.max_wall_seconds) or a.max_wall_seconds <= 0:
-        p.error("GPU timing requires a finite positive --max-wall-seconds")
-    if not os.environ.get("CUDA_VISIBLE_DEVICES") or "," in os.environ["CUDA_VISIBLE_DEVICES"]:
-        p.error("Root must select exactly one verified idle GPU via CUDA_VISIBLE_DEVICES")
-    if a.output.exists() and any(a.output.iterdir()):
-        p.error("Output must be empty/new")
-    a.output.mkdir(parents=True, exist_ok=True)
-    deadline = time.monotonic() + a.max_wall_seconds
-    h, _ = r.helpers(a.source)
-
-    from contextlib import ExitStack
-    from CelerisLab.cuda.context import CudaContext
-    from CelerisLab.lbm.refinement_stepper import FixedPatchStepper
-    from CelerisLab.lbm.channel import channel_masks
-    from CelerisLab.lbm.refinement import ACTIVE
-    from CelerisLab.lbm.descriptors import SOLID
-
-    rows, ref = [], {}
-    n_intervals = a.base_steps // INTERVAL
-    with ExitStack() as stack:
-        cfg, pair, body, host = r.host_geometry(a.source, h, "MRT")
-        context = stack.enter_context(CudaContext(0))
-        backend = stack.enter_context(FixedPatchStepper(
-            cfg, r.BOUNDS, context=context, coarse_boundary="channel", base_block=r.BASE_BLOCK,
-            fine_block=r.FINE_BLOCK, fine_objects=(body,), observe_raw_exchange=True,
-            observe_window_exchange=True))
-        masks = [channel_masks(pair.coarse_shape)[0] & ~pair.covered,
-                 (pair.fine_kind == ACTIVE) & ((host.flags.reshape(pair.fine_shape) & SOLID) == 0)]
-        fresh = (r.initial_state(pair.coarse_shape, (0.0, 0.0), 1.0, root=True),
-                 r.initial_state(pair.fine_shape, pair.fine_origin, 0.5))
-        print(json.dumps(dict(status="CONSTRUCTED", case="refined")), flush=True)
-        for repeat in range(a.repeats):
-            for variant in VARIANTS:
-                t.check_deadline(deadline)
-                backend.initialize(*fresh)
-                for _ in range(a.warmup_base_steps):
-                    backend.step(1)
-                warm = t.refined_health(backend, masks)
-                if repeat == 0 and variant == "A":
-                    print(json.dumps(dict(status="WARM_READY", case="refined")), flush=True)
-                t.sync_refined(backend)
-                start = time.perf_counter()
-                totals, scales = run_variant(backend, variant, n_intervals, deadline)
-                t.sync_refined(backend)
-                seconds = time.perf_counter() - start
-                end = t.refined_health(backend, masks)
-                values = [np.array(v, copy=True) for v in backend._download_raw().values]
-                if variant == "A" and repeat == 0:
-                    ref.update(values=values, totals=totals, scales=scales)
-                    parity, ratio = "identical", 0.0
-                else:
-                    parity = t.same_state(ref["values"], values) or "identical"
-                    ratio = compare_intervals(ref["totals"], ref["scales"], totals)
-                rows.append(dict(variant=variant, repeat=repeat, seconds=seconds,
-                                 intervals=n_intervals, population_parity_vs_A=parity,
-                                 interval_impulse_violation_ratio=ratio,
-                                 health_after_warmup=warm, health_after_window=end))
-                if parity != "identical" or not ratio <= 1:
-                    raise RuntimeError(f"{variant} repeat {repeat}: parity {parity}, impulse ratio {ratio}")
-    summary = {v: dict(median_seconds=statistics.median(x["seconds"] for x in rows if x["variant"] == v),
-                       seconds=[x["seconds"] for x in rows if x["variant"] == v]) for v in VARIANTS}
-    summary.update(W_over_A=summary["W"]["median_seconds"] / summary["A"]["median_seconds"],
-                   W1_over_A=summary["W1"]["median_seconds"] / summary["A"]["median_seconds"],
-                   interpretation="Measured comparative timings under GPU variability; W also "
-                                  "batches step calls, W1 isolates the read pattern. Not a "
-                                  "benchmark-throughput or causal claim.")
-    (a.output / "window_timing.json").write_text(json.dumps(dict(plan=plan, rows=rows, summary=summary),
-                                                           indent=2))
-    print(json.dumps(summary, indent=2), flush=True)
-    return 0
-
-
-if __name__ == "__main__":
-    sys.exit(main())

tests/validation/uniform_srt_diagnostic/cpu_test_results.txt

@@ -0,0 +1,12 @@
+unittest.case.FunctionTestCase (test_bounded_state_evidence) ... ok
+unittest.case.FunctionTestCase (test_disjoint_complete_categories) ... ok
+unittest.case.FunctionTestCase (test_exact_config_and_source) ... ok
+unittest.case.FunctionTestCase (test_inactive_nonfinite_does_not_fail) ... ok
+unittest.case.FunctionTestCase (test_original_safety_limits) ... ok
+unittest.case.FunctionTestCase (test_population_macro_force_separate) ... ok
+unittest.case.FunctionTestCase (test_source_guard_and_deadline) ... ok
+
+----------------------------------------------------------------------
+Ran 7 tests in 0.039s
+
+OK

tests/validation/uniform_srt_diagnostic/diagnose_uniform_srt.py

@@ -0,0 +1,219 @@
+"""Read-only observations of the exact failed SRT control, at most 320 steps.
+
+Default is CPU preflight. Execution requires root admission and an external watchdog.
+No solver, initialization, geometry or numerical parameter modifications.
+"""
+import argparse
+import hashlib
+import importlib
+import json
+import math
+import os
+from pathlib import Path
+import sys
+import time
+from tempfile import TemporaryDirectory
+
+import numpy as np
+
+HERE=Path(__file__).resolve().parent
+DEFAULT_SOURCE=HERE.parents[2]
+LIMIT_BYTES=128*1024**2
+
+
+def dump(path,value):
+    path.write_text(json.dumps(value,indent=2,allow_nan=False))
+
+
+def number(value):
+    value=float(value)
+    return value if math.isfinite(value) else ('NaN' if math.isnan(value) else ('+Inf' if value>0 else '-Inf'))
+
+
+def source_config(source):
+    manifest=json.loads((HERE/'source_manifest.json').read_text())
+    for name,digest in manifest['sha256'].items():
+        if hashlib.sha256((source/name).read_bytes()).hexdigest()!=digest:
+            raise ValueError('Pinned source mismatch: '+name)
+    sys.path.insert(0,str(source/'src')); sys.path.insert(0,str(source/'tests/validation'))
+    import CelerisLab
+    if Path(CelerisLab.__file__).resolve()!=source/'src/CelerisLab/__init__.py':
+        raise ValueError('Wrong CelerisLab import')
+    runner=importlib.import_module('run_refined_dfg')
+    if Path(runner.__file__).resolve()!=source/'tests/validation/run_refined_dfg.py':
+        raise ValueError('Wrong runner import')
+    h,_=runner.helpers(source)
+    cfg,body,p=runner.config(h,80)  # Exact original config factory, not a reimplementation.
+    return cfg,body,p,manifest
+
+
+def categories(flags,p):
+    """Disjoint physical categories; subtype nibble is not a bitfield."""
+    from CelerisLab.lbm.descriptors import FLUID,SOLID,OBSTACLE
+    y,x=np.indices(flags.shape); fluid=(flags&FLUID)!=0
+    masks={}; left=fluid.copy()
+    for name,test in (
+        ('body_near',(x-p['center'][0])**2+(y-p['center'][1])**2 <= (p['radius']+3)**2),
+        ('outlet_near',x>=flags.shape[1]-4),('inlet_near',x<=3),
+        ('wall_near',(y<=3)|(y>=flags.shape[0]-4))):
+        masks[name]=left&test; left &= ~test
+    masks['bulk']=left
+    subtype=flags&0xf0
+    masks['inlet_ghost']=(~fluid)&(subtype==0x20)
+    masks['outlet_ghost']=(~fluid)&(subtype==0x30)
+    masks['wall_ghost']=(~fluid)&(subtype==0x10)
+    assigned=np.logical_or.reduce(list(masks.values()))
+    masks['body_solid']=(~assigned)&(((flags&OBSTACLE)!=0)|((flags&SOLID)!=0))
+    assigned|=masks['body_solid']; masks['other_inactive']=~assigned
+    return fluid,masks
+
+
+def finite_extrema(a,mask):
+    good=mask&np.isfinite(a)
+    if not good.any(): return dict(min=None,max=None)
+    idx=np.flatnonzero(good); values=a.ravel()[idx]
+    lo=int(idx[np.argmin(values)]); hi=int(idx[np.argmax(values)])
+    return dict(min=float(a.ravel()[lo]),max=float(a.ravel()[hi]),
+                min_yx=list(map(int,np.unravel_index(lo,a.shape))),
+                max_yx=list(map(int,np.unravel_index(hi,a.shape))))
+
+
+def diagnose(g,macro,force,flags,p,step):
+    fluid,masks=categories(flags,p)
+    badpop=~np.isfinite(g); badnode=badpop.any(axis=0)
+    badmacro=np.logical_or.reduce([~np.isfinite(macro[k]) for k in ('rho','ux','uy')])
+    with np.errstate(over='ignore',invalid='ignore'):
+        mach=np.sqrt(3*(np.asarray(macro['ux'],np.float64)**2+np.asarray(macro['uy'],np.float64)**2))
+    rho=macro['rho']
+    # Exactly the original physical macro/reaction conditions, now sampled each step.
+    nonfinite_macro=bool(np.any(badmacro&fluid))
+    force_bad=force is not None and not np.isfinite(force).all()
+    density_bad=bool(np.any(fluid&((rho<.5)|(rho>1.5))))
+    mach_bad=bool(np.any(fluid&(mach>.2)))
+    population_bad=bool(np.any(badnode&fluid))
+    original_failure=nonfinite_macro or force_bad or density_bad or mach_bad
+    offending=fluid&(badnode|badmacro|(rho<.5)|(rho>1.5)|(mach>.2))
+    examples=[]
+    for y,x in np.argwhere(offending)[:16]:
+        examples.append(dict(y=int(y),x=int(x),physical_xy_m=[float(x*p['dx']),float((y-.5)*p['dx'])],
+            category=next(name for name,mask in masks.items() if mask[y,x]),flag=int(flags[y,x]),
+            nonfinite_q=np.flatnonzero(badpop[:,y,x]).tolist(),
+            populations=[number(v) for v in g[:,y,x]],
+            rho=number(rho[y,x]),ux=number(macro['ux'][y,x]),uy=number(macro['uy'][y,x])))
+    neighborhoods=[]
+    for node in examples[:4]:
+        y,x=node['y'],node['x']; y0,y1=max(0,y-2),min(flags.shape[0],y+3); x0,x1=max(0,x-2),min(flags.shape[1],x+3)
+        neighborhoods.append(dict(bounds_xy=[x0,y0,x1,y1],flags=flags[y0:y1,x0:x1].tolist(),
+            physical_populations=[[[number(v) for v in row] for row in plane] for plane in g[:,y0:y1,x0:x1]]))
+    return dict(step=step,tstar=step*p['mean_speed']/p['diameter'],
+        physical_failure=bool(original_failure or population_bad),
+        original_health_failure=bool(original_failure),
+        physical_population_nonfinite=population_bad,physical_macro_nonfinite=nonfinite_macro,
+        force_nonfinite=bool(force_bad),density_limit=density_bad,mach_limit=mach_bad,
+        force=None if force is None else [number(v) for v in force],
+        categories={name:dict(nodes=int(mask.sum()),nonfinite_population_nodes=int((mask&badnode).sum()),
+            nonfinite_populations=int(badpop[:,mask].sum()),nonfinite_macro_nodes=int((mask&badmacro).sum()))
+            for name,mask in masks.items()},
+        rho=finite_extrema(rho,fluid),mach=finite_extrema(mach,fluid),
+        first_physical_examples=examples,local_neighborhoods=neighborhoods)
+
+
+def snapshot(sim,p):
+    # Public physical decode and original production macro path. No host reconstruction
+    # substitutes for the original health check. get_ddf shares its completed-step cache.
+    with np.errstate(all='ignore'):
+        macro={k:np.asarray(v).copy() for k,v in sim.get_macroscopic().items()}
+        g=sim.get_ddf().reshape(9,p['ny'],p['nx'])
+    import pycuda.driver as cuda
+    raw=np.empty_like(g,dtype=np.float32)
+    with sim.ctx.activate():
+        cuda.memcpy_dtoh(raw,sim.field.ddf_gpu)
+    return dict(raw=raw,g=g,macro=macro,step=int(sim.stepper.step_count))
+
+
+def save_states(dest,previous,current,flags,diagnostic):
+    """Two states only; raw shifted bits and decoded observations, no trajectory."""
+    arrays={'flags':flags}
+    for name,state in (('previous',previous),('current',current)):
+        if state is None: continue
+        arrays[name+'_raw_shifted']=state['raw']
+        arrays[name+'_physical']=state['g']
+        arrays[name+'_step']=np.array(state['step'],np.int64)
+    # At D80, raw+physical for two states ~84 MiB; reserve >4 MiB for JSON/NPZ overhead.
+    if sum(v.nbytes for v in arrays.values())>LIMIT_BYTES-4*1024**2:
+        raise ValueError('Evidence arrays exceed bounded artifact budget')
+    np.savez(dest/'states.npz',**arrays)
+    dump(dest/'diagnostics.json',diagnostic)
+    size=sum(p.stat().st_size for p in dest.iterdir() if p.is_file())
+    if size>LIMIT_BYTES: raise RuntimeError('Evidence directory exceeds 128 MiB')
+    return size
+
+
+def deadline_check(deadline):
+    if time.monotonic()>=deadline: raise TimeoutError('Diagnostic wall ceiling reached')
+
+
+def execute(a,cfg,body,p):
+    from CelerisLab.simulation import Simulation
+    started=time.monotonic(); deadline=started+a.wall_seconds
+    previous=None; prior_report=None; initial_report=None
+    with TemporaryDirectory() as temp:
+        temp=Path(temp); dump(temp/'lbm.json',cfg); dump(temp/'body.json',body)
+        with Simulation(str(temp/'lbm.json'),str(temp/'body.json'),device_id=0) as sim:
+            sim.initialize()  # Exact original production initialization, unchanged.
+            flags=sim.get_flags().reshape(p['ny'],p['nx'])
+            current=snapshot(sim,p)
+            initial_report=diagnose(current['g'],current['macro'],None,flags,p,0)
+            report=initial_report; status='initial_physical_failure' if report['physical_failure'] else 'step_cap_reached'
+            try:
+                deadline_check(deadline)
+                if not report['physical_failure']:
+                    for _ in range(320):
+                        deadline_check(deadline)
+                        previous=current; prior_report=report
+                        sim.run(1)  # Same solver; observation buffers reset/read once per step.
+                        force=sim.read_force(0).astype(np.float64)
+                        current=snapshot(sim,p)
+                        report=diagnose(current['g'],current['macro'],force,flags,p,current['step'])
+                        if current['step']==1:
+                            print('READY '+json.dumps(dict(step=1,all_observation_paths_exercised=True,
+                                physical_healthy=not report['physical_failure']),allow_nan=False),flush=True)
+                        if report['physical_failure']:
+                            status='first_physical_failure'; break
+                        deadline_check(deadline)
+            except TimeoutError:
+                status='wall_time_limit'
+            details=dict(status=status,executed_steps=int(sim.stepper.step_count),
+                observation_step=current['step'],previous_observation_step=None if previous is None else previous['step'],
+                initial=initial_report,preceding=prior_report,current=report,
+                wall_seconds=time.monotonic()-started,
+                storage='raw_shifted FP32 is exact active-buffer data; physical is production FP32 decoded G. Both are diagnostic snapshots, not complete restart checkpoints.',
+                health_scope='Physical FLUID nodes and force only; ghost/body categories cannot independently trigger physical failure.',
+                interpretation='Near-region labels locate symptoms, not the root cause. Per-step inspection changes observation cadence only. No physical acceptance.')
+            size=save_states(a.output,previous,current,flags,details)
+            print(json.dumps(dict(status=status,executed_steps=int(sim.stepper.step_count),evidence_bytes=size),allow_nan=False),flush=True)
+            return 0 if status=='step_cap_reached' else 2
+
+
+def main():
+    parser=argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--source',type=Path,default=DEFAULT_SOURCE)
+    parser.add_argument('--output',type=Path,required=True)
+    parser.add_argument('--execute',action='store_true')
+    parser.add_argument('--gpu-admitted',action='store_true')
+    parser.add_argument('--wall-seconds',type=float)
+    a=parser.parse_args(); a.source=a.source.resolve()
+    cfg,body,p,manifest=source_config(a.source)
+    if a.output.exists() and any(a.output.iterdir()): raise ValueError('Use a new/empty output directory')
+    if a.execute and (not a.gpu_admitted or not os.environ.get('CUDA_VISIBLE_DEVICES') or
+            a.wall_seconds is None or not math.isfinite(a.wall_seconds) or a.wall_seconds<=0):
+        raise ValueError('Explicit root admission, device selection and finite wall ceiling required')
+    a.output.mkdir(parents=True,exist_ok=True)
+    dump(a.output/'preflight.json',dict(source=manifest,config=cfg,body=body,parameters=p,
+        diagnostic_sha256=hashlib.sha256(Path(__file__).read_bytes()).hexdigest(),max_steps=320,
+        max_evidence_bytes=LIMIT_BYTES,executed=False))
+    if not a.execute: return 0
+    return execute(a,cfg,body,p)
+
+
+if __name__=='__main__': raise SystemExit(main())

tests/validation/uniform_srt_diagnostic/source_manifest.json

@@ -1,7 +1,6 @@
 {
-  "commit": "3ea131e92c057843034f11a1c574301a2430dfce",
-  "production_origin_commit": "3ea131e92c057843034f11a1c574301a2430dfce",
-  "collision": "MRT",
+  "commit": "9805383f9c50d867e8555471baf5dbda8333a652",
+  "failure_source_receipt_sha256": "a77f71550c52d4b8b6e946a3cb98fc5de5db3da1bcbbb3457c6d60167677ce4e",
   "sha256": {
     "src/CelerisLab/__init__.py": "21cc469bd6e970a1f9ff5970c8eea4602065e41fc881854759ee565ee55c10c6",
     "src/CelerisLab/body/__init__.py": "e4e0e8f0769a94428d5b02fac790443997556cfc5515a5f1ed1595d2c694d69d",
@@ -44,14 +43,14 @@
     "src/CelerisLab/lbm/__init__.py": "7f60fb3aaae81501b510d08c2fedff44fcb05657260eb10b6f5cc91e7204306b",
     "src/CelerisLab/lbm/block_stepper.py": "00b313daddc6e63d8ab8423c9190ca7e92ad291de20a2f6b80eb53e3f2d85ec7",
     "src/CelerisLab/lbm/blocks.py": "1e644c5719993f418185ad4a10b6950a30636fc912befd9eab41ff48b4cf85cd",
-    "src/CelerisLab/lbm/channel.py": "40d0354e5dc97bcdb7e7b5c1e7f9303a109b7134d8a3af88b8ff4cd75ab5a095",
+    "src/CelerisLab/lbm/channel.py": "2d5b5ff43414cb35633ac4ce90ce2c3a3353950b25c168e1c2ab58d498dd8b0f",
     "src/CelerisLab/lbm/curved_links.py": "b6957fa13d13f864dba4f7364e93a39905d062dbb3ee9b3f5191add81fff0732",
     "src/CelerisLab/lbm/descriptors.py": "c9f025dfc14da43b989047b84cc22bd05d5cc92c9ec695c1da68fdfb788e3f2b",
     "src/CelerisLab/lbm/equilibrium.py": "2fb2f2bb7ff326d23abce80fc2a4c0907b17740ea3e29fe6ae079c5044783826",
     "src/CelerisLab/lbm/field.py": "0e727eacc3706add4d8d15c418e9b631050871f831698d3ac689dd5f2c701b9b",
     "src/CelerisLab/lbm/hierarchy.py": "f234975074f6b6d289d573ff6ea6832feae0e27cb04f80b37fe81792b13a12e7",
     "src/CelerisLab/lbm/initializers.py": "dacf9586963e862d6d0a98ef1a066036be6f91e9d423720661d8ef2c1fb2df6a",
-    "src/CelerisLab/lbm/kernels/blocks.cu": "2fa894b20a29f006911ac3e3aad0793cc4aaf9ccd7a67d01c6320a0836b1d8ef",
+    "src/CelerisLab/lbm/kernels/blocks.cu": "e3b9606f861bfea8c4b0f34e8356bb230081f899c584f67be89178d889099b17",
     "src/CelerisLab/lbm/kernels/boundary/bounce_back.cuh": "aba3748c564ed91b161d268ef8b737b7c7be96a823063d201f3da684dd845233",
     "src/CelerisLab/lbm/kernels/boundary/curved_boundary.cuh": "aeb16bfd483514fb03e15a2fed437d673c3b8b2fe68ab83edf4244ef593878ea",
     "src/CelerisLab/lbm/kernels/boundary/esopull_curved_helpers.cuh": "b9b474bc4edaff05681c5443235472d04072d0d775fc0eb9c5967faef52b0258",
@@ -64,12 +63,12 @@
     "src/CelerisLab/lbm/kernels/boundary/inlet_outlet.cuh": "de8b213a6da42c2e5e9f8966199fc66ea4541b85144a90f3f5dbad3c6ab63b97",
     "src/CelerisLab/lbm/kernels/boundary/outlet/pressure_neq.cuh": "c8b2adc66d12fe602076ddc9693c5c208711fcaddb58aa9a31401a269f51c4c4",
     "src/CelerisLab/lbm/kernels/boundary/planar_velocity.cuh": "501b2759d0e2e4280cb6fdd127d66a50fa89f6de48fc2cae9a7eafb11ae90bed",
+    "src/CelerisLab/lbm/kernels/config.h": "7d1124125e0b354558297934460e64c760fb68cdd7bf6d01a1238bb2eaab8c37",
     "src/CelerisLab/lbm/kernels/config/config_grid.h": "1db3e030ebdc116cd7f02362d1fd077daac55e8f0b4329f6285948c224d3ca5d",
     "src/CelerisLab/lbm/kernels/config/config_method.h": "4374e04a130f90f97d17cc20c40d2f9ea0ed0dd8603817d07f215d02266e247c",
     "src/CelerisLab/lbm/kernels/config/config_objects.h": "db793af052c756561a190a3ff2cb93ee5fe28462ee4f97c6af80882b4dc8b072",
     "src/CelerisLab/lbm/kernels/config/config_obs.h": "c11e2249359145b5c4cbaaf0487506fa77c1f4b82c7c169ddc574aa0babcd727",
     "src/CelerisLab/lbm/kernels/config/config_physics.h": "8ac0990b168e1058588676cc05c80df8634cfd671dbc92a89246c3c372d83a4e",
-    "src/CelerisLab/lbm/kernels/config.h": "7d1124125e0b354558297934460e64c760fb68cdd7bf6d01a1238bb2eaab8c37",
     "src/CelerisLab/lbm/kernels/core/descriptors.cuh": "8440bc14857da9007982650f828a23608eec9f7cc4bf772e8c8dc1239cb45356",
     "src/CelerisLab/lbm/kernels/core/flags.cuh": "0025705f24710330d9d9195f713879bfb650a85a3449baef0e196b831af104ab",
     "src/CelerisLab/lbm/kernels/core/layout.cuh": "1fbd820021c89ac3efcde24145996cb0147769e607e498e61f308ed3e0b13706",
@@ -84,9 +83,9 @@
     "src/CelerisLab/lbm/kernels/operators/helpers.cuh": "0b3a4d95d7d19f5fec09e5423b8f4cc99f8a226b541967425967330da5a051ec",
     "src/CelerisLab/lbm/kernels/operators/macro.cuh": "2be20eb2b7d7f5522daaad7f4b57b1ff8cdf883efe4a67846a96783b2fe846a3",
     "src/CelerisLab/lbm/kernels/operators/turbulence_smag.cuh": "ff7f000297ee0817e255ad9fcb6a13b647e3ddd5b206518d35f38d2895a9f501",
-    "src/CelerisLab/lbm/kernels/refinement.cu": "b45aad9c022cecb64f7e968ec3cae2d8385a3cc430ee409700c404a3f4dd8cf8",
+    "src/CelerisLab/lbm/kernels/refinement.cu": "129f3d91da93b4324f88a0da73a4da1e5390f72c14cce574ee63306712da9895",
     "src/CelerisLab/lbm/kernels/step/aux_kernels.cu": "578a5b20a157241ee678547059abb1372dd5a589ad06bb2c15b987eb01ca1013",
-    "src/CelerisLab/lbm/kernels/step/block_channel.cu": "ee8a31398b8e5233d977c816e6b8e060c1eb2ec71320e594226dbca55593c0d0",
+    "src/CelerisLab/lbm/kernels/step/block_channel.cu": "befbf6d757e532a59c166d41f920d16d71557cd3a574478e7aa83da737c48cbd",
     "src/CelerisLab/lbm/kernels/step/curved_double.cu": "bfa7a1df1e939020314d49755045f7a85fe4a19cc1c68dbe62653c66c5e7c2b3",
     "src/CelerisLab/lbm/kernels/step/esopull_macro.cu": "c73116020ca217ede1e4de27c8269c31f9d91e33433ac8252a21e9b14187c50f",
     "src/CelerisLab/lbm/kernels/step/esopull_sync.cu": "c0ff3e72900c3ab89a05dd03684e96d3b740cf1672d565727fc2af165933d087",
@@ -98,15 +97,16 @@
     "src/CelerisLab/lbm/kernels/streaming/pull_double_buffer.cuh": "b65d741ed78b7b62f99531ba0c0ce1936663d8dc9640e7d7d16c707f1baf6549",
     "src/CelerisLab/lbm/population_storage.py": "a6a86c29c52c892edfe4802fb773c387212e3f4cc86708d80e154986ddf88044",
     "src/CelerisLab/lbm/raw_exchange.py": "8694202466eba848563e298656353b0f5db94e21a01fa05f51aad6dc2b9fd311",
-    "src/CelerisLab/lbm/refinement.py": "100d5e46ac894f6008b61364cdad5d37c2ca7ed949d8d71405572d6366526417",
+    "src/CelerisLab/lbm/refinement.py": "08c2a0557276a98cbcaa459d9bb7a9735d8bbbf64a6114c57af2fda61481a687",
     "src/CelerisLab/lbm/refinement_stepper.py": "f2bb34fa90805ad21c3e7cf9f9a67d88d3ae3e249b4517d3898567b4bf9e364d",
     "src/CelerisLab/lbm/refinement_tables.py": "fdd344024b89df3a83174dc810ca5e32db5e19eb8b1609f8f73b0821f56546b6",
     "src/CelerisLab/lbm/stepper.py": "0dcb7cd7ae87e33e3dc67a38b6aa43042fbe673e37d9ad165342ee1d695933ce",
     "src/CelerisLab/lbm/synchronized_remap.py": "7400fc4beaffd4649d6a9c524d38ce5fd6fa7eeb32eb5332e4030a4b6648f197",
     "src/CelerisLab/simulation.py": "0a03904dc6de88667d7af699005a289adf8b09f0976cb0d099b041f4830a8f4c",
-    "tests/validation/re100_helpers.py": "289c6e01075ff361573f862b90cfd61e5980c9a8efcbc78aef69979b4004fd60",
+    "tests/validation/data/refined_dfg/source_manifest.json": "e495948b10f8112c77ca67255122b5e8bc9e32570e8c899802afcb85e608fef4",
     "tests/validation/periodic.py": "a2212c0e2705126327a5019e9cafe64eeca398da1b75061ff23630c9843697a6",
-    "tests/validation/data/dfg_re100/reference_cycle.json": "073d1bda1629697efebad95667bfe80598e217d708dbffd7d5f6c6999379c55f",
+    "tests/validation/re100_helpers.py": "289c6e01075ff361573f862b90cfd61e5980c9a8efcbc78aef69979b4004fd60",
+    "tests/validation/run_refined_dfg.py": "256aacd84b3f8412a31ffaba9c4b5635db895c3177686dd34ef8e31f08119414",
     "tests/validation/source_provenance.py": "6dfe8f2d819dba0e240ba761d31162a5033685d492d09db75eb2b8aaab3a5a4c"
   }
-}
+}

tests/validation/uniform_srt_diagnostic/test_diagnostic.py

@@ -0,0 +1,100 @@
+"""CPU-only synthetic diagnostic and source-contract tests; no simulation results."""
+import json
+from pathlib import Path
+import sys
+from tempfile import TemporaryDirectory
+import unittest
+import numpy as np
+sys.path.insert(0,str(Path(__file__).resolve().parent))
+import diagnose_uniform_srt as d
+cfg,body,p,manifest=d.source_config(d.DEFAULT_SOURCE)
+
+
+def fixture():
+    flags=np.ones((12,20),np.uint16)
+    flags[:,0]=2|0x20; flags[:,-1]=2|0x30
+    flags[[0,-1]]=2|0x10; flags[5,6]=2|0x40|0x200
+    g=np.full((9,12,20),1/9,np.float32)
+    macro=dict(rho=np.ones((12,20)),ux=np.zeros((12,20)),uy=np.zeros((12,20)))
+    params=dict(center=[6,5],radius=1,dx=.1,mean_speed=.01,diameter=80)
+    return g,macro,flags,params
+
+
+def test_exact_config_and_source():
+    assert manifest['commit']=='9805383f9c50d867e8555471baf5dbda8333a652'
+    assert p['diameter']==80 and p['mean_speed']==.01 and p['nx']==1761 and p['ny']==330
+    assert cfg['method']['collision']=='SRT' and cfg['method']['ddf_shifting']
+    assert cfg['method']['outlet']['srt_neq_damp']==.5
+    assert np.isclose(3*p['viscosity']+.5,.524)
+    assert body['objects'][0]['center']==[160,160.5]
+
+
+def test_inactive_nonfinite_does_not_fail():
+    g,m,f,p=fixture(); fluid,_=d.categories(f,p)
+    g[:,~fluid]=np.nan
+    for a in m.values(): a[~fluid]=np.nan
+    r=d.diagnose(g,m,np.zeros(2),f,p,1)
+    assert not r['physical_failure']
+    assert r['categories']['body_solid']['nonfinite_population_nodes']==1
+    assert r['categories']['outlet_ghost']['nodes']==10
+    assert r['categories']['inlet_ghost']['nodes']==10
+    json.dumps(r,allow_nan=False)
+
+
+def test_population_macro_force_separate():
+    g,m,f,p=fixture(); g[4,6,17]=np.inf
+    r=d.diagnose(g,m,np.zeros(2),f,p,27)
+    assert r['physical_failure'] and r['physical_population_nonfinite']
+    assert not r['original_health_failure'] and not r['force_nonfinite']
+    assert r['first_physical_examples'][0]['category']=='outlet_near'
+    assert r['first_physical_examples'][0]['nonfinite_q']==[4]
+    assert r['first_physical_examples'][0]['populations'][4]=='+Inf'
+    json.dumps(r,allow_nan=False)
+    g,m,f,p=fixture(); m['ux'][6,10]=np.nan
+    r=d.diagnose(g,m,np.zeros(2),f,p,28)
+    assert r['physical_macro_nonfinite'] and not r['physical_population_nonfinite']
+    assert not r['force_nonfinite'] and r['original_health_failure']
+    g,m,f,p=fixture(); r=d.diagnose(g,m,np.array([np.nan,0]),f,p,29)
+    assert r['force_nonfinite'] and not r['physical_macro_nonfinite']
+    assert not r['first_physical_examples']
+
+
+def test_original_safety_limits():
+    g,m,f,p=fixture(); m['rho'][5,7]=.49
+    r=d.diagnose(g,m,[0,0],f,p,1)
+    assert r['density_limit'] and r['first_physical_examples'][0]['category']=='body_near'
+    g,m,f,p=fixture(); m['ux'][6,10]=.2
+    assert d.diagnose(g,m,[0,0],f,p,1)['mach_limit']
+
+
+def test_disjoint_complete_categories():
+    _,_,f,p=fixture(); fluid,masks=d.categories(f,p)
+    np.testing.assert_array_equal(sum(mask.astype(int) for mask in masks.values()),np.ones(f.shape))
+    physical=sum(masks[k].astype(int) for k in ('body_near','inlet_near','outlet_near','wall_near','bulk'))
+    np.testing.assert_array_equal(physical,fluid.astype(int))
+
+
+def test_bounded_state_evidence():
+    g,m,f,p=fixture(); state=dict(raw=g.copy(),g=g,macro=m,step=1)
+    with TemporaryDirectory() as tmp:
+        dest=Path(tmp); size=d.save_states(dest,state,state,f,{'status':'synthetic_test'})
+        assert size<d.LIMIT_BYTES
+        with np.load(dest/'states.npz') as saved:
+            np.testing.assert_array_equal(saved['previous_raw_shifted'],g)
+            np.testing.assert_array_equal(saved['current_physical'],g)
+        assert sorted(x.name for x in dest.iterdir())==['diagnostics.json','states.npz']
+    actual_bytes=4*(9*330*1761*4)+(330*1761*2)+16
+    assert actual_bytes<d.LIMIT_BYTES-4*1024**2
+
+
+def test_source_guard_and_deadline():
+    with TemporaryDirectory() as tmp:
+        with unittest.TestCase().assertRaises((ValueError,FileNotFoundError)):
+            d.source_config(Path(tmp))
+    with unittest.TestCase().assertRaises(TimeoutError): d.deadline_check(0)
+
+
+if __name__=='__main__':
+    result=unittest.TextTestRunner(verbosity=2).run(unittest.TestSuite(
+        unittest.FunctionTestCase(fn) for name,fn in sorted(globals().items()) if name.startswith('test_')))
+    raise SystemExit(not result.wasSuccessful())