Make `trapz` accept 1-D `x` parameter for n-d `y`, even if axis != -1.

Additional tests included.

1 files changed, 11 insertions, 3 deletions

diff --git a/numpy/lib/function_base.py b/numpy/lib/function_base.py
index 425960639..269a97721 100644
--- a/numpy/lib/function_base.py
+++ b/numpy/lib/function_base.py
@@ -2818,9 +2818,9 @@ def trapz(y, x=None, dx=1.0, axis=-1):
     y : array_like
         Input array to integrate.
     x : array_like, optional
-        If `x` is None, then spacing between all `y` elements is 1.
+        If `x` is None, then spacing between all `y` elements is `dx`.
     dx : scalar, optional
-        If `x` is None, spacing given by `dx` is assumed.
+        If `x` is None, spacing given by `dx` is assumed. Default is 1.
     axis : int, optional
         Specify the axis.
 
@@ -2836,7 +2836,15 @@ def trapz(y, x=None, dx=1.0, axis=-1):
     if x is None:
         d = dx
     else:
-        d = diff(x,axis=axis)
+        x = asarray(x)
+        if x.ndim == 1:
+            d = diff(x)
+            # reshape to correct shape
+            shape = [1]*y.ndim
+            shape[axis] = d.shape[0]
+            d = d.reshape(shape)
+        else:
+            d = diff(x, axis=axis)
     nd = len(y.shape)
     slice1 = [slice(None)]*nd
     slice2 = [slice(None)]*nd