Merge pull request #8629 from eric-wieser/speedup-indices

ENH: Improve the efficiency of indices

1 files changed, 4 insertions, 7 deletions

diff --git a/numpy/core/numeric.py b/numpy/core/numeric.py
index b90b0a9c9..97d19f008 100644
--- a/numpy/core/numeric.py
+++ b/numpy/core/numeric.py
@@ -2089,15 +2089,12 @@ def indices(dimensions, dtype=int):
     """
     dimensions = tuple(dimensions)
     N = len(dimensions)
-    if N == 0:
-        return array([], dtype=dtype)
+    shape = (1,)*N
     res = empty((N,)+dimensions, dtype=dtype)
     for i, dim in enumerate(dimensions):
-        tmp = arange(dim, dtype=dtype)
-        tmp.shape = (1,)*i + (dim,)+(1,)*(N-i-1)
-        newdim = dimensions[:i] + (1,) + dimensions[i+1:]
-        val = zeros(newdim, dtype)
-        add(tmp, val, res[i])
+        res[i] = arange(dim, dtype=dtype).reshape(
+            shape[:i] + (dim,) + shape[i+1:]
+        )
     return res