Hi, thank you for your comments and your hints (I probably deserve some kind of subtle irony). I found the problem:
I thought a numpy array A has shape (n,) but actually it had shape (n,1). In the loop I sampled a value from that array: v.append(A[i]) So what happened was that I got a view of A not a single number and append obviously appended the whole array not just a single element array. And n is about 64000. So sorry for bothering you with that stupid fault. Regards Rolf -- http://mail.python.org/mailman/listinfo/python-list
