[Cython] RuntimeWarning: numpy.dtype size changed when cimporting numpy

Richard Sharp richsharp at stanford.edu
Fri Mar 2 07:29:25 CET 2012


I have a largish cython module that outputs the following warnings
every time I import the compiled module.

__main__:1: RuntimeWarning: numpy.dtype size changed, may indicate
binary incompatibility
__main__:1: RuntimeWarning: numpy.flatiter size changed, may indicate
binary incompatibility

Is this something I should worry about?  I've traced this warning gets
generated when a `cimport numpy as np` line is processed in my module.
 When I comment out that line I don't get any warning.  To recreate
this error I've created a cython with only that line as follows:

numpy_test.pyx:

cimport numpy as np

A barebones setup in `setup.py`:

from distutils.core import setup
from distutils.extension import Extension
from Cython.Distutils import build_ext

setup(name='numpy_test',
      version='tip',
      cmdclass={'build_ext': build_ext},
      ext_modules=[Extension(name="numpy_test", sources=['numpy_test.pyx'])]
      )

Then I do a local build like this:
python setup.py build

cd into the build directory:
cd build/lib.linux-x86_64-2.6/

verify the .so is there:
$ ls
numpy_test.so

and import it and get the runtime warning:
$ python -c "import numpy_test"
-c:1: RuntimeWarning: numpy.dtype size changed, may indicate binary
incompatibility
-c:1: RuntimeWarning: numpy.flatiter size changed, may indicate binary
incompatibility

I'm running 64 bit Ubuntu 10.04, Python 2.6.6, and Cython 0.15.1.

Any help would be greatly appreciated!

Rich

--
Richard P. Sharp Jr.
Lead Software Developer
Natural Capital Project
Stanford University, U Minnesota, TNC, WWF
371 Serra Mall
Stanford, CA 94305
http://www.stanford.edu/~rpsharp/


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