compiler: Remove useless IndexDerivative properties

devito/finite_differences/differentiable.py

@@ -735,9 +735,9 @@ def _xreplace(self, rule):
 
 class IndexDerivative(IndexSum):
 
-    __rargs__ = ('expr', 'mapper', 'order')
+    __rargs__ = ('expr', 'mapper')
 
-    def __new__(cls, expr, mapper, order, **kwargs):
+    def __new__(cls, expr, mapper, **kwargs):
         dimensions = as_tuple(set(mapper.values()))
 
         # Detect the Weights among the arguments
@@ -758,12 +758,11 @@ def __new__(cls, expr, mapper, order, **kwargs):
         obj = super().__new__(cls, expr, dimensions)
         obj._weights = weights
         obj._mapper = frozendict(mapper)
-        obj._order = order
 
         return obj
 
     def _hashable_content(self):
-        return super()._hashable_content() + (self.mapper, self.order)
+        return super()._hashable_content() + (self.mapper,)
 
     def compare(self, other):
         if self is other:
@@ -787,14 +786,6 @@ def weights(self):
     def mapper(self):
         return self._mapper
 
-    @property
-    def order(self):
-        return self._order
-
-    @property
-    def scaling(self):
-        return Mul(*[d.spacing**self.order for d in self.mapper])
-
     @property
     def depth(self):
         iderivs = self.expr.find(IndexDerivative)
@@ -936,7 +927,7 @@ def _diff2sympy(obj):
 
         # Handle special objects
         if isinstance(obj, DiffDerivative):
-            return IndexDerivative(*args, obj.mapper, obj.order), True
+            return IndexDerivative(*args, obj.mapper), True
 
         # Handle generic objects such as arithmetic operations
         try:

devito/finite_differences/finite_difference.py

@@ -247,7 +247,7 @@ def make_derivative(expr, dim, fd_order, deriv_order, side, matvec, x0, symbolic
             # Pure number
             pass
 
-        deriv = DiffDerivative(expr*weights, {dim: indices.free_dim}, deriv_order)
+        deriv = DiffDerivative(expr*weights, {dim: indices.free_dim})
     else:
         terms = []
         for i, c in zip(indices, weights):

tests/test_derivatives.py

@@ -6,7 +6,7 @@
                     ConditionalDimension, left, right, centered, div, grad)
 from devito.finite_differences import Derivative, Differentiable
 from devito.finite_differences.differentiable import (Add, EvalDerivative, IndexSum,
-                                                      IndexDerivative, Weights, Pow)
+                                                      IndexDerivative, Weights)
 from devito.symbolics import indexify, retrieve_indexed
 from devito.types.dimension import StencilDimension
 
@@ -716,9 +716,8 @@ def test_index_derivative(self):
         ui = u.subs(x, x + i*x.spacing)
         w = Weights(name='w0', dimensions=i, initvalue=[-0.5, 0, 0.5])
 
-        idxder = IndexDerivative(ui*w, {x: i}, so)
+        idxder = IndexDerivative(ui*w, {x: i})
 
-        assert idxder.scaling == Pow(x.spacing, so)
         assert idxder.evaluate == -0.5*u + 0.5*ui.subs(i, 2)
 
         # Make sure subs works as expected
@@ -727,7 +726,7 @@ def test_index_derivative(self):
         vi0 = v.subs(x, x + i*x.spacing)
         vi1 = idxder.subs(ui, vi0)
 
-        assert IndexDerivative(vi0*w, {x: i}, so) == vi1
+        assert IndexDerivative(vi0*w, {x: i}) == vi1
 
     def test_dx2(self):
         grid = Grid(shape=(4, 4))