Merge pull request #2934 from devitocodes/warn-if-shrunk-bounds

dsl: Warn if shrinking SpaceDimension bounds

Author: FabioLuporini

devito/operator/operator.py

@@ -43,6 +43,7 @@
 )
 from devito.types import Buffer, Evaluable, device_layer, disk_layer, host_layer
 from devito.types.dimension import Thickness
+from devito.warnings import warn
 
 __all__ = ['Operator']
 
@@ -688,8 +689,15 @@ def _prepare_arguments(self, autotune=None, estimate_memory=False, **kwargs):
             p._arg_check(args, self._dspace[p], am=self._access_modes.get(p),
                          **kwargs)
         for d in self.dimensions:
+            try:
+                if d.is_Space and any(self._dspace[d].offsets):
+                    warn(f"Shrinking bounds (`{d.min_name}`, `{d.max_name}`); "
+                         f"some `{d}` points will not be computed. Likely "
+                         "insufficient space_order for the derivatives.")
+            except AttributeError:
+                pass
             if d.is_Derived:
-                d._arg_check(args, self._dspace[p])
+                d._arg_check(args)
 
         # Turn arguments into a format suitable for the generated code
         # E.g., instead of NumPy arrays for Functions, the generated code expects

tests/test_operator.py

@@ -38,6 +38,7 @@
 from devito.types import (
     Array, Barrier, ConditionalDimension, CustomDimension, Indirection, Scalar, Symbol
 )
+from devito.warnings import DevitoWarning
 
 
 def dimify(dimensions):
@@ -1343,6 +1344,22 @@ def test_apply_args_consitency(self, vfact):
             if isinstance(v, int):
                 assert args1[k] == v
 
+    def test_warn_if_shrunk_spacedim_bounds(self):
+        grid = Grid(shape=(20, 20))
+
+        f = Function(name='f', grid=grid, space_order=0)
+        u = TimeFunction(name='u', grid=grid, space_order=8)
+
+        eq = Eq(u.forward, u + (u*f).laplace)
+
+        op = Operator(eq)
+
+        u.data[:] = 2.
+        f.data[:] = 3.
+
+        with pytest.warns(DevitoWarning, match="Shrinking bounds*"):
+            op.apply(time_M=3)
+
 
 @skipif('device')
 class TestDeclarator: