[Numpy-discussion] Impossibility to build nipy on recent numpy?

Gael Varoquaux gael.varoquaux@normalesup....
Wed Dec 9 15:31:46 CST 2009

In the nipy project, we have cython-generated C files checked in. 
With the latest numpy I get the following run-time failure:

line 6, in <module>
    from routines import _joint_histogram, _similarity,
  File "numpy.pxi", line 74, in nipy.neurospin.register.routines
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

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.


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