api: remove un-necessary extra eqs and temp for gridpoint precomputed

devito/operations/interpolators.py

@@ -432,11 +432,11 @@ class PrecomputedInterpolator(WeightedInterpolator):
     _name = 'precomp'
 
     def _positions(self, implicit_dims):
-        if self.sfunction.gridpoints is None:
+        if self.sfunction.gridpoints_data is None:
             return super()._positions(implicit_dims)
-        # No position temp as we have directly the gridpoints
-        return [Eq(p, floor(k), implicit_dims=implicit_dims)
-                for (k, p) in self.sfunction._position_map.items()]
+        else:
+            # No position temp as we have directly the gridpoints
+            return []
 
     @property
     def interpolation_coeffs(self):

devito/types/sparse.py

@@ -1154,11 +1154,10 @@ def _position_map(self):
         the position. We mitigate this problem by computing the positions
         individually (hence the need for a position map).
         """
-        if self.gridpoints is not None:
+        if self.gridpoints_data is not None:
             ddim = self.gridpoints.dimensions[-1]
-            return OrderedDict((self.gridpoints._subs(ddim, di), p)
-                               for (di, p) in zip(range(self.grid.dim),
-                                                  self._pos_symbols))
+            return OrderedDict((d, self.gridpoints._subs(ddim, i))
+                               for (i, d) in enumerate(self.grid.dimensions))
         else:
             return super()._position_map