compiler: fix dimension sort determinism

devito/ir/equations/algorithms.py

@@ -74,7 +74,7 @@ def handle_indexed(indexed):
     # obtain the desired ordering `(time, x, xi)`. W/o `(time, x)`, the ordering
     # `(x, time, xi)` might be returned instead, which would be non-sense
     for i in relations:
-        dims = [di for d in i for di in (d.index, d)]
+        dims = [di for d in i for di in (d.root, d)]
         implicit_relations.update({tuple(filter_ordered(dims))})
 
     ordering = PartialOrderTuple(extra, relations=(relations | implicit_relations))

devito/operations/interpolators.py

@@ -176,22 +176,25 @@ def _interp_idx(self, variables, implicit_dims=None):
         """
         mapper = {}
         pos = self.sfunction._position_map.values()
-        # Temporaries for the position
-        temps = self._positions(implicit_dims)
 
-        # Coefficient symbol expression
-        temps.extend(self._coeff_temps(implicit_dims))
         for ((di, d), rd, p) in zip(enumerate(self._gdims), self._rdim, pos):
             # Add conditional to avoid OOB
             lb = sympy.And(rd + p >= d.symbolic_min - self.r, evaluate=False)
             ub = sympy.And(rd + p <= d.symbolic_max + self.r, evaluate=False)
             cond = sympy.And(lb, ub, evaluate=False)
             mapper[d] = ConditionalDimension(rd.name, rd, condition=cond, indirect=True)
 
+        # Temporaries for the position
+        temps = self._positions(implicit_dims)
+
+        # Coefficient symbol expression
+        temps.extend(self._coeff_temps(implicit_dims))
+
         # Substitution mapper for variables
         idx_subs = {v: v.subs({k: c - v.origin.get(k, 0) + p
                     for ((k, c), p) in zip(mapper.items(), pos)})
                     for v in variables}
+        idx_subs.update(dict(zip(self._rdim, mapper.values())))
 
         return idx_subs, temps