In inverse_permutation, use same dtype as permutation. Test updated.

theano/tensor/basic.py

@@ -3625,7 +3625,10 @@ def inverse_permutation(perm):
     """Computes the inverse of permutations.
     Each row of input should contain a permutation of the first integers.
     """
-    return permute_row_elements(arange(perm.shape[-1]), perm, inverse=True)
+    return permute_row_elements(
+            arange(perm.shape[-1], dtype=perm.dtype),
+            perm,
+            inverse=True)
 
 #########################
 # Advanced indexing

theano/tensor/tests/test_basic.py

@@ -2759,6 +2759,7 @@ class TestInversePermutation(unittest.TestCase):
         """Test the inversion of one permutation (int vector)"""
         p = ivector()
         inv = inverse_permutation(p)
+        assert inv.dtype == p.dtype
         f_inverse = function([p], inv)
 
         # Generate a random permutation