Fix overflow error in cartesian_product

When the numbers in `X` are large it can cause an overflow error on windows machine where the native `int` is 32 bit. Switching to np.intp alleviates this problem.

Other fixes would include switching to np.uint32 or np.uint64.

Author: david-hoffman

pandas/tools/util.py

@@ -55,7 +55,7 @@ def cartesian_product(X):
     if len(X) == 0:
         return []
 
-    lenX = np.fromiter((len(x) for x in X), dtype=int)
+    lenX = np.fromiter((len(x) for x in X), dtype=np.intp)
     cumprodX = np.cumproduct(lenX)
 
     a = np.roll(cumprodX, 1)