[Numpy-discussion] try to solve issue #2649 and revisit #473

huangkandiy@gmai... huangkandiy@gmai...
Wed Apr 3 14:18:09 CDT 2013


I know matrix will call the dot function of ndarray. However, that will not
give the answer we expect. A 5*5 matrix multiplies another matrix, we
expect answer to be error or a 5*? matrix, not a 1*5 matrix.

As ticket 2649 said, I * I * x or I.dot(I.dot(x)) should be as same as I *
x. But it will return an error because I and I.dot(x) are not aligned.



On Wed, Apr 3, 2013 at 2:50 PM, Alan G Isaac <alan.isaac@gmail.com> wrote:

> On 4/3/2013 2:44 PM, huangkandiy@gmail.com wrote:
> > I suggest add function dot to matrix
>
>  >>> import numpy as np; x = np.arange(5); I = np.asmatrix(np.identity(5));
>  >>> I.dot(x)
> matrix([[ 0.,  1.,  2.,  3.,  4.]])
>
>
> Alan Isaac
>
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-- 
Kan Huang
Department of Applied math & Statistics
Stony Brook University
917-767-8018
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