Fix finding norm for numpy 1.7

dstansby · dstansby · commit 021aaa49eda6 · 2017-09-10T17:09:35.000+01:00
diff --git a/lib/matplotlib/contour.py b/lib/matplotlib/contour.py
@@ -402,7 +402,9 @@ def calc_label_rot_and_inline(self, slc, ind, lw, lc=None, spacing=5):
 
         def _path_length(X):
             dX = np.diff(X, axis=0)
-            dX = np.linalg.norm(dX, axis=1)
+            # Alternative to np.linalg.norm()
+            # as numpy 1.7 doesn't have 'axis' kwarg
+            dX = np.sum(dX**2, axis=1)**(1 / 2)
             return np.concatenate((np.zeros(1), np.cumsum(dX)))
         pl = _path_length(slc)
         pl = pl - pl[ind]
