test: compare all-dense MRT fine stepping with blocked layouts

tests/validation/multigrid/test_refinement_mrt_gpu.py

@@ -53,23 +53,24 @@ class RefinementMRTGPU(unittest.TestCase):
                             else:
                                 for a, b in zip(reference, raw.values): np.testing.assert_array_equal(a, b)
 
-    def test_dense_versus_blocked_root_mrt_two_level(self):
+    def test_dense_versus_blocked_mrt_two_level(self):
-        """Unshifted MRT: dense root (PatchCoarseStep) vs blocked root (BlockStep), same fine blocks."""
+        """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 = {}
-            for base_block in (None, *BASE_BLOCKS):
+            layouts = ((None, None), *((base, FINE_BLOCK) for base in (None, *BASE_BLOCKS)))
-                with FixedPatchStepper(cfg, BOUNDS, context=context, fine_block=FINE_BLOCK,
+            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] = raw(backend)
+                    results[base_block, fine_block] = raw(backend)
-            for base_block in BASE_BLOCKS:
+            for layout in layouts[1:]:
-                for level, (a, b) in enumerate(zip(results[base_block], results[None])):
+                for level, (a, b) in enumerate(zip(results[layout], results[None, None])):
-                    exact(self, a, b, f"base={base_block} level={level}")
+                    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."""