api: prevent sympy warnings with diag

Author: mloubout

devito/finite_differences/elementary.py

@@ -2,7 +2,6 @@
 from packaging.version import Version
 
 from devito.finite_differences.differentiable import DifferentiableFunction, diffify
-from devito.types.lazy import Evaluable
 
 
 class factorial(DifferentiableFunction, sympy.factorial):
@@ -89,13 +88,13 @@ def root(x):
     return diffify(sympy.root(x))
 
 
-class Min(sympy.Min, Evaluable):
+class Min(sympy.Min, DifferentiableFunction):
 
     def _evaluate(self, **kwargs):
         return self.func(*self._evaluate_args(**kwargs), evaluate=False)
 
 
-class Max(sympy.Max, Evaluable):
+class Max(sympy.Max, DifferentiableFunction):
 
     def _evaluate(self, **kwargs):
         return self.func(*self._evaluate_args(**kwargs), evaluate=False)

devito/finite_differences/operators.py

@@ -1,3 +1,6 @@
+from sympy import S
+
+
 def div(func, shift=None, order=None, method='FD', side=None, **kwargs):
     """
     Divergence of the input Function.
@@ -194,6 +197,6 @@ def diag(func, size=None):
     to = getattr(func, 'time_order', 0)
 
     tens_func = TensorTimeFunction if func.is_TimeDependent else TensorFunction
-    comps = [[func if i == j else 0 for i in range(dim)] for j in range(dim)]
+    comps = [[func if i == j else S.Zero for i in range(dim)] for j in range(dim)]
     return tens_func(name='diag', grid=func.grid, space_order=func.space_order,
                      components=comps, time_order=to, diagonal=True)

devito/passes/clusters/implicit.py

@@ -189,6 +189,7 @@ def key(tkn):
 
         # Turn the reduced mapper into a list of equations
         processed = []
+
         for bunch in found.values():
             exprs = make_implicit_exprs(bunch.mapper)