[Numpy-discussion] persistent ImportError: No module named multiarray when moving cPickle files between machines

Bruce Southey bsouthey at gmail.com
Mon Nov 2 17:43:56 EST 2009

On Mon, Nov 2, 2009 at 2:42 PM, Reckoner <reckoner at gmail.com> wrote:
> Anybody have any ideas here?
> Otherwise, I'm thinking this should be posted to the numpy bugs list.
> What's the best way to report a bug of this kind?
> Thanks!
> On Fri, Oct 30, 2009 at 5:48 PM, Reckoner <reckoner at gmail.com> wrote:
>>> Robert Kern wrote:
>>> You can import numpy.core.multiarray on both machines?
>> Yes. For each machine separately, you can cPickle files with numpy
>> arrays without problems loading/dumping. The problem comes from
>> transferring the win32 cPickle'd files to Linux 64 bit and then trying
>> to load them. Transferring cPickle'd files that do *not* have numpy
>> arrays work as expected. In other words, cPICKLE'd lists transfer fine
>> back and forth between the two machines. In fact, we currently get
>> around this problem by converting the numpy arrays to lists,
>> transferring them, and then re-numpy-ing them on the respective hosts
>> thanks.
>> On Fri, Oct 30, 2009 at 11:13 AM, Reckoner <reckoner at gmail.com> wrote:
>>> Hi,
>>> % python -c 'import numpy.core.multiarray'
>>> works just fine, but when I try to load a file that I have transferred
>>> from another machine running Windows to one running Linux, I get:
>>> %  python -c 'import cPickle;a=cPickle.load(open("matrices.pkl"))'
>>> Traceback (most recent call last):
>>>  File "<string>", line 1, in <module>
>>> ImportError: No module named multiarray
>>> otherwise, cPickle works normally when transferring files that *do*
>>> not contain numpy arrays.
>>> I am using version 1.2 on both machines. It's not so easy for me to
>>> change versions, by the way, since this is the version that my working
>>> group has decided on to standardize on for this effort.
>>> Any help appreciated.
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Have you have tried the other Cookbook approaches:
Like using numpy's own array io functions - load/save(z)?
(seems to work between 64-bit Windows 7 and 64-bit Linux - each has
different numpy versions)


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