In the nipy project, we have cython-generated C files checked in. With the latest numpy I get the following run-time failure: "/home/varoquau/dev/nipy-trunk/nipy/neurospin/register/iconic_matcher.py", line 6, in <module> from routines import _joint_histogram, _similarity, similarity_measures File "numpy.pxi", line 74, in nipy.neurospin.register.routines (nipy/neurospin/register/routines.c:6042) ValueError: numpy.dtype does not appear to be the correct type object Where routines.c is a cython-generated file. I suspect that this is due to the recent change in the size of the struct representing numpy arrays. With other projects, it was sufficient to recompile the project to avoid this problem. With nipy it is not. Could that be because the cython-generated C file encodes the size of the numpy array struct, and has been compiled with a different numpy? If this is the case, I think that it means that we need to all use the same version of numpy (1.3). Does anybody know if the cython folks are going to work around that anytime soon (I am not on the cython mailing list, so I am not asking there)? Nipy folks, does that mean that we should change our policy, and build the cython-generated c files at compile time, thus requiring cython as a build dependency? Any comments appreciated. Gaël