ClaudeandClaude Opus 5.5
e4049a6183
d_params and the block wall/channel constants are per-module runtime globals, immutable per stepper instance but not visible to the compiler. Note that dense and blocked slot roots carry the wall slot as macros vs d_block_wall respectively. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
26 lines
3.0 KiB
Markdown
26 lines
3.0 KiB
Markdown
# Device state lifecycle (uniform Simulation, PeriodicBlockStepper, FixedPatchStepper)
|
|
|
|
State is grouped by what a change invalidates. This file describes the code as
|
|
it is; it adds no framework. Line references are to candidate 0f8fdbc3.
|
|
|
|
| Class | Contents | How it changes | Owner rule |
|
|
|---|---|---|---|
|
|
| 1. Module and its globals | Compile-time (visible to the compiler, fixed per module): `config.h` macros incl. `NX`/`NY`, `COLLISION_MODEL`, `BLOCK_ROOT_BC`, `WALL_*`. Runtime per-module globals (not visible to the compiler; written by host code): `__constant__` `d_params`, `d_w`, `d_cx`, `d_cy`, `d_block_channel`, `d_block_wall`; plus bound kernel handles | Globals are written once by the owner right after `load_module`. Uniform grid: `Simulation._recompile` (construction, body-topology sync) loads a new module and re-uploads; `update_runtime_params` rewrites `d_params` (omega, force, n_objects) between runs. Steppers: never rewritten after construction, so they are immutable for the instance's lifetime although they are runtime values. The same quantity can be a macro in one route and a global in another (dense slot root: `WALL_SLOT_WIDTH`/`WALL_NORMAL_VELOCITY` macros; blocked slot root: `d_block_wall`), which can change generated arithmetic. | Every owner loads its own module (`compiler_v2.load_module` = `module_from_file`, no cache). A loaded module is never shared between live owners: globals are per module, so sharing would share mutable `d_params`. |
|
|
| 2. Geometry, layout, tables | flags, curved-link tables, block layouts and halo pairs, transfer (explode/coalesce) tables, block kinds | Immutable for the life of an instance. Uniform grid: rebuilt by body sync. `FixedPatchStepper`: a geometry change is a new instance (`remap_child`), committed only after a successful transfer. | No in-place table edits. |
|
|
| 3. Controls and dependent boundary columns | Jet amplitude -> per-link `surface_velocity`; body actions (uniform grid) | Between steps, without a table or module rebuild (`set_jet_amplitude`). | Host copy commits only after the device upload succeeded; a device error fails the instance. |
|
|
| 4. Per-step state | population double buffers and their parity, raw-exchange ledgers, observations | Device-only during `step(n)` / `run(n)`; buffer swaps are host-handle swaps. | Valid on the host only after the single wait at the end of the call. |
|
|
|
|
Storage routes are separate concerns:
|
|
|
|
- Original uniform grid (`kernel_v2.cu`, `Simulation`): whole-domain `NX`/`NY`.
|
|
- Blocked levels (`blocks.cu`; `PeriodicBlockStepper` and every blocked
|
|
`FixedPatchStepper` level): `NX`/`NY` are one block window including halo.
|
|
- Dense refinement levels (`refinement.cu`, `level_blocks[l] is None`).
|
|
|
|
A single-rectangle refinement (`FixedPatch2D`) is stored in its own fine
|
|
window frame in both dense and blocked form (`refinement_stepper.py:222-224`,
|
|
`BlockLayout2D.build(*pair.fine_shape, ...)`). Only a rectangle set
|
|
(`FixedPatchSet2D`) uses the level-wide frame `(2*ny, 2*nx)`, whose
|
|
`fine_layout` requires that full grid to be divisible by the tile
|
|
(`refinement.py:240-252`).
|