MAINT: Use moveaxis instead of rollaxis internally (#9475)

Also add a hint to the documentation advising the use of moveaxis over rollaxis.

Tests for rollaxis are left alone.

1 files changed, 5 insertions, 5 deletions

diff --git a/numpy/polynomial/polynomial.py b/numpy/polynomial/polynomial.py
index 4b343bf7d..1528de342 100644
--- a/numpy/polynomial/polynomial.py
+++ b/numpy/polynomial/polynomial.py
@@ -546,7 +546,7 @@ def polyder(c, m=1, scl=1, axis=0):
     if cnt == 0:
         return c
 
-    c = np.rollaxis(c, iaxis)
+    c = np.moveaxis(c, iaxis, 0)
     n = len(c)
     if cnt >= n:
         c = c[:1]*0
@@ -558,7 +558,7 @@ def polyder(c, m=1, scl=1, axis=0):
             for j in range(n, 0, -1):
                 der[j - 1] = j*c[j]
             c = der
-    c = np.rollaxis(c, 0, iaxis + 1)
+    c = np.moveaxis(c, 0, iaxis)
     return c
 
 
@@ -662,7 +662,7 @@ def polyint(c, m=1, k=[], lbnd=0, scl=1, axis=0):
         return c
 
     k = list(k) + [0]*(cnt - len(k))
-    c = np.rollaxis(c, iaxis)
+    c = np.moveaxis(c, iaxis, 0)
     for i in range(cnt):
         n = len(c)
         c *= scl
@@ -676,7 +676,7 @@ def polyint(c, m=1, k=[], lbnd=0, scl=1, axis=0):
                 tmp[j + 1] = c[j]/(j + 1)
             tmp[0] += k[i] - polyval(lbnd, tmp)
             c = tmp
-    c = np.rollaxis(c, 0, iaxis + 1)
+    c = np.moveaxis(c, 0, iaxis)
     return c
 
 
@@ -1147,7 +1147,7 @@ def polyvander(x, deg):
         v[1] = x
         for i in range(2, ideg + 1):
             v[i] = v[i-1]*x
-    return np.rollaxis(v, 0, v.ndim)
+    return np.moveaxis(v, 0, -1)
 
 
 def polyvander2d(x, y, deg):