The Windows_XP buildbot shows several warnings about npy_intp -> int conversions. Two of them look OK, but probably explicit casts should be made. The third is: numpy\core\src\ufuncobject.c(2422) : warning C4244: '=' : conversion from 'npy_intp' to 'int', possible loss of data Which looks possibly legitimate to me. Unfortunately, it looks like fixing it involves a change in the loop type. Chuck