api: improve backward compatibility of new factor

Author: mloubout

devito/deprecations.py

@@ -27,5 +27,12 @@ def subdomain_warn(self):
              DeprecationWarning, stacklevel=2)
         return
 
+    @cached_property
+    def constant_factor_warn(self):
+        warn("Using a `Constant` as a factor when creating a ConditionalDimension"
+             " is deprecated. Use an integer instead.",
+             DeprecationWarning, stacklevel=2)
+        return
+
 
 deprecations = DevitoDeprecation()

devito/types/dimension.py

@@ -7,11 +7,13 @@
 import numpy as np
 
 from devito.data import LEFT, RIGHT
+from devito.deprecations import deprecations
 from devito.exceptions import InvalidArgument
 from devito.logger import debug
 from devito.tools import Pickable, is_integer, is_number, memoized_meth
 from devito.types.args import ArgProvider
 from devito.types.basic import Symbol, DataSymbol, Scalar
+from devito.types.constant import Constant
 
 
 __all__ = ['Dimension', 'SpaceDimension', 'TimeDimension', 'DefaultDimension',
@@ -920,8 +922,9 @@ def __init_finalize__(self, name, parent=None, factor=None, condition=None,
         elif is_number(factor):
             self._factor = int(factor)
         elif factor.is_Constant:
-            self._factor = factor.data
-            fname = factor.name
+            deprecations.constant_factor_warn
+            self._factor = factor
+            symbolic_factor = factor
         else:
             raise ValueError("factor must be an integer or integer Constant")
 
@@ -937,7 +940,14 @@ def __init_finalize__(self, name, parent=None, factor=None, condition=None,
 
     @property
     def spacing(self):
-        return self.factor * self.parent.spacing
+        return self.factor_data * self.parent.spacing
+
+    @property
+    def factor_data(self):
+        if isinstance(self.factor, Constant):
+            return self.factor.data
+        else:
+            return self.factor
 
     @property
     def factor(self):
@@ -970,7 +980,7 @@ def _arg_values(self, interval, grid=None, args=None, **kwargs):
         if self.symbolic_factor is not None:
             fname = self.symbolic_factor.name
             args = args or {}
-            fact = kwargs.get(fname, args.get(fname, self.factor))
+            fact = kwargs.get(fname, args.get(fname, self.factor_data))
         else:
             # No factor
             return {}
@@ -1000,7 +1010,7 @@ def _arg_defaults(self, _min=None, size=None, alias=None):
         # up to the caller to decide which one to pick upon reduction
         dim = alias or self
         if dim.symbolic_factor is not None:
-            factor = defaults[dim.symbolic_factor.name] = self.factor
+            factor = defaults[dim.symbolic_factor.name] = self.factor_data
             defaults[dim.parent.max_name] = range(0, factor*size - 1)
 
         return defaults

tests/test_dimension.py

@@ -1916,6 +1916,23 @@ def test_cond_copy(self):
         op = Operator([Eq(u.forward, u.laplace), Eq(u12, u), Eq(u22, u)])
         assert len([p for p in op.parameters if p.name == 'tsubf']) == 1
 
+    def test_const_factor(self):
+        grid = Grid(shape=(4, 4))
+        time = grid.time_dim
+
+        f1 = 4
+        f2 = Constant(name='f2', dtype=np.int32, value=4)
+        t1 = ConditionalDimension('t_sub', parent=time, factor=f1)
+        t2 = ConditionalDimension('t_sub2', parent=time, factor=f2)
+
+        assert isinstance(t1.symbolic_factor, Scalar)
+        assert t1.factor == f1
+
+        assert t2.symbolic_factor.is_Constant
+        assert t2.factor == f2
+        assert t2.factor.data == f1
+        assert t2.spacing == t1.spacing
+
 
 class TestCustomDimension: