[SciPy-User] Sparse matrix multiply
Thu Mar 22 05:08:47 CDT 2012
On 03/22/2012 12:07 PM, Jaakko Luttinen wrote:
> On 03/22/2012 12:03 PM, Christopher Mutel wrote:
>> On Thu, Mar 22, 2012 at 10:34 AM, Jaakko Luttinen
>> <email@example.com> wrote:
>>> Why do I get two different results for the code below?
>>> import numpy as np
>>> import scipy.sparse as sp
>>> A = sp.rand(20,20,density=0.1)
>>> B = sp.rand(20,20,density=0.1)
>>> # out: 21.058793740984925
>>> # out: 0.76482546226069481
>>> Am I missing something?
>>> I think numpy.multiply should either return the correct answer or an
>>> error that it can't compute the correct answer.
>> np.multiply performs element-wise multiplication, while A.multiply is
>> matrix multiplication. They are both "correct", but answer different
> Is it so..?
> I don't know what "point-wise multiplication" means..
> Anyway, I thought that dot computes matrix multiplication and multiply
> computes matrix multiplication.
TYPOFIX: I thought that multiply computes element-wise multiplication.
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