MAINT: use normalize_axis_index in np.roll

Interestingly np.roll allows axes to be repeated.

1 files changed, 4 insertions, 6 deletions

diff --git a/numpy/core/numeric.py b/numpy/core/numeric.py
index e1352ee6c..afa10747c 100644
--- a/numpy/core/numeric.py
+++ b/numpy/core/numeric.py
@@ -1460,16 +1460,14 @@ def roll(a, shift, axis=None):
         return roll(a.ravel(), shift, 0).reshape(a.shape)
 
     else:
+        axis = _validate_axis(axis, a.ndim, allow_duplicate=True)
         broadcasted = broadcast(shift, axis)
         if broadcasted.ndim > 1:
             raise ValueError(
                 "'shift' and 'axis' should be scalars or 1D sequences")
         shifts = {ax: 0 for ax in range(a.ndim)}
         for sh, ax in broadcasted:
-            if -a.ndim <= ax < a.ndim:
-                shifts[ax % a.ndim] += sh
-            else:
-                raise ValueError("'axis' entry is out of bounds")
+            shifts[ax] += sh
 
         rolls = [((slice(None), slice(None)),)] * a.ndim
         for ax, offset in shifts.items():
@@ -1544,13 +1542,13 @@ def rollaxis(a, axis, start=0):
     return a.transpose(axes)
 
 
-def _validate_axis(axis, ndim, argname=None):
+def _validate_axis(axis, ndim, argname=None, allow_duplicate=False):
     try:
         axis = [operator.index(axis)]
     except TypeError:
         axis = list(axis)
     axis = [normalize_axis_index(ax, ndim, argname) for ax in axis]
-    if len(set(axis)) != len(axis):
+    if not allow_duplicate and len(set(axis)) != len(axis):
         if argname:
             raise ValueError('repeated axis in `%s` argument' % argname)
         else: