diff --git a/wafo/kdetools/gridding.py b/wafo/kdetools/gridding.py
index f2e3cfd..dec00da 100644
--- a/wafo/kdetools/gridding.py
+++ b/wafo/kdetools/gridding.py
@@ -215,7 +215,7 @@ def accum(accmap, a, func=None, shape=None, fill_value=0, dtype=None):
 
     # Create the output array.
     out = np.empty(shape, dtype=dtype)
-    for s in product(*[np.arange(k) for k in shape]):
+    for s in product(*[list(range(k)) for k in shape]):
         if vals[s] == []:
             out[s] = fill_value
         else:
@@ -249,7 +249,7 @@ def _gridcount_nd(acfun, data, x, y, w, binx):
 
     c = np.reshape(c / w, c_shape, order='F')
 
-    T = np.arange(d).tolist()
+    T = list(range(d))
     T[1], T[0] = T[0], T[1]
     # make sure c is stored in the same way as meshgrid
     c = c.transpose(*T)
diff --git a/wafo/misc.py b/wafo/misc.py
index a974ccf..1b14dfb 100644
--- a/wafo/misc.py
+++ b/wafo/misc.py
@@ -204,13 +204,15 @@ def piecewise(condlist, funclist, xi=None, fill_value=0.0, args=(), **kw):
     if xi is None:
         arrays = ()
         dtype = np.result_type(*funclist)
+        shape = condlist[0].shape
     else:
         if not isinstance(xi, tuple):
             xi = (xi,)
         arrays = np.broadcast_arrays(*xi)
         dtype = np.result_type(*arrays)
+        shape = arrays[0].shape
 
-    out = valarray(condlist[0].shape, fill_value, dtype)
+    out = valarray(shape, fill_value, dtype)
     for cond, func in zip(condlist, funclist):
         if cond.any():
             if isinstance(func, collections.Callable):