api: fix indexification of staggered functions after dimension subs

devito/builtins/initializers.py

@@ -366,7 +366,7 @@ def initialize_function(function, data, nbl, mapper=None, mode='constant',
         raise NotImplementedError("TimeFunctions are not currently supported.")
 
     if nbl == 0:
-        for f in functions:
+        for f, data in zip(functions, datas):
             if isinstance(data, dv.Function):
                 f.data[:] = data.data[:]
             else:
@@ -382,7 +382,7 @@ def initialize_function(function, data, nbl, mapper=None, mode='constant',
 
         assert len(lhss) == len(rhss) == len(optionss)
 
-        name = name or 'pad_%s' % '_'.join(f.name for f in functions)
+        name = name or 'initialize_%s' % '_'.join(f.name for f in functions)
         assign(lhss, rhss, options=optionss, name=name, **kwargs)
 
     if pad_halo:

devito/types/basic.py

@@ -1245,8 +1245,15 @@ def indexify(self, indices=None, subs=None):
         subs = [{**{d.spacing: 1, -d.spacing: -1}, **subs} for d in self.dimensions]
 
         # Indices after substitutions
-        indices = [sympy.sympify(a.subs(d, d - o).xreplace(s)) for a, d, o, s in
-                   zip(self.args, self.dimensions, self.origin, subs)]
+        indices = []
+        for a, d, o, s in zip(self.args, self.dimensions, self.origin, subs):
+            if d in a.free_symbols:
+                # Shift by origin d -> d - o.
+                indices.append(sympy.sympify(a.subs(d, d - o).xreplace(s)))
+            else:
+                # Dimension has been removed, e.g. u[10], plain shift by origin
+                indices.append(sympy.sympify(a - o).xreplace(s))
+
         indices = [i.xreplace({k: sympy.Integer(k) for k in i.atoms(sympy.Float)})
                    for i in indices]
 

tests/test_builtins.py

@@ -333,8 +333,8 @@ def test_batching(self):
         a = np.arange(16).reshape((4, 4))
 
         f = Function(name='f', grid=grid, dtype=np.int32)
-        g = Function(name='g', grid=grid, dtype=np.int32)
-        h = Function(name='h', grid=grid, dtype=np.int32)
+        g = Function(name='g', grid=grid, dtype=np.float32)
+        h = Function(name='h', grid=grid, dtype=np.float64)
 
         initialize_function([f, g, h], [a, a, a], 4, mode='reflect')
 

tests/test_symbolics.py

@@ -132,6 +132,17 @@ def test_indexed():
     assert ub.indexed.free_symbols == {ub.indexed}
 
 
+def test_indexed_staggered():
+    grid = Grid(shape=(10, 10))
+    x, y = grid.dimensions
+    hx, hy = x.spacing, y.spacing
+
+    u = Function(name='u', grid=grid, staggered=(x, y))
+    u0 = u.subs({x: 1, y: 2})
+    assert u0.indices == (1 + hx / 2, 2 + hy / 2)
+    assert u0.indexify().indices == (1, 2)
+
+
 def test_bundle():
     grid = Grid(shape=(4, 4))