test: prepare matched shifted GPU spacing ladder

tests/validation/multigrid/spacetime_table_guard.py

@@ -1,4 +1,4 @@
-"""N64 admission check: exact topology and independently rational interpolation.
+"""N64/N128 admission check: exact topology and independently rational interpolation.
 
 Raw FP64 bytes are diagnostic: different LAPACK builds need not produce them
 identically. The 2e-14 ceiling is the existing interpolation constraint policy,
@@ -11,6 +11,8 @@ import numpy as np
 from spacetime_gpu import table_hash
 
 STRUCTURE_SHA = 'cd1842952c4dd4df82da8015454c25da9be12b983270236cc65b4044fa38e6e4'
+STRUCTURES = {64: (STRUCTURE_SHA, 532),
+              128: ('ee4ecb645674ae04eb87220a5217851405ccc0f45fbb0fe210499dcea5cd93b1', 1060)}
 ATOL = 2e-14
 
 
@@ -57,13 +59,14 @@ def exact_weights(kind, points):
     return np.array(_multiply(e,solution[:4]), dtype=np.float64)
 
 
-def validate_tables(plan, tables):
+def validate_tables(plan, tables, *, allow_n128=False):
     """Reject topology, layout, padding, operator, or constraint changes separately."""
     structure = table_hash({key:value for key,value in tables.items() if key != 'weights'})
-    if plan.n != 64 or structure != STRUCTURE_SHA:
+    admitted = (64,128) if allow_n128 is True else (64,)
+    if plan.n not in admitted or structure != STRUCTURES[plan.n][0]:
         raise ValueError('frozen integer topology changed')
     w = tables['weights']
-    if (w.dtype != np.dtype(np.float64) or w.shape != (532,4,10) or len(plan.groups) != w.shape[0]
+    if (w.dtype != np.dtype(np.float64) or w.shape != (STRUCTURES[plan.n][1],4,10) or len(plan.groups) != w.shape[0]
             or not all(a.flags.c_contiguous for a in tables.values()) or not np.isfinite(w).all()):
         raise ValueError('weight dtype/shape/layout/finiteness changed')
     errors = dict(coefficient=0., constant=0., mean=0., temporal=0.)