Discussion of Numerical Python

bob tnur | 18 Jun 2012 17:55

convert any non square matrix in to square matrix using numpy

Hi,

how I can convert (by adding zero) of any non-square numpy matrix in to square matrix using numpy? then how to find the minimum number in each row except the zeros added(for making square matrix)? ;)

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Tony Yu | 18 Jun 2012 19:04

Re: convert any non square matrix in to square matrix using numpy

On Mon, Jun 18, 2012 at 11:55 AM, bob tnur <bobtnur78 <at> gmail.com> wrote:

Hi,

how I can convert (by adding zero) of any non-square numpy matrix in to square matrix using numpy? then how to find the minimum number in each row except the zeros added(for making square matrix)? ;)

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Hi Bob,

I'm not quite sure what you're looking for (esp. the second question), but maybe something like the following?

#~~~ example code

import numpy as np

nonsquare = np.random.random(size=(3, 5))

M, N = nonsquare.shape

width = max(M, N)

square = np.zeros((width, width))

square[:M, :N] = nonsquare

min_rows = np.min(nonsquare, axis=1)

#~~~

-Tony

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eat | 18 Jun 2012 19:22

Re: convert any non square matrix in to square matrix using numpy

Hi,

On Mon, Jun 18, 2012 at 6:55 PM, bob tnur <bobtnur78 <at> gmail.com> wrote:

Hi,

how I can convert (by adding zero) of any non-square numpy matrix in to square matrix using numpy? then how to find the minimum number in each row except the zeros added(for making square matrix)? ;)

Perhaps something like this:

In []: def make_square(A):

..: s= A.shape

..: if s[0]< s[1]:

....: return r_[A, zeros((s[1]- s[0], s[1]), dtype= A.dtype)]

..: return c_[A, zeros((s[0], s[0]- s[1]), dtype= A.dtype)]

..:

In []: A= rand(4, 2)

In []: make_square(A)

Out[]:

array([[ 0.76109774, 0.42980812, 0. , 0. ],

[ 0.11810978, 0.59622975, 0. , 0. ],

[ 0.54991376, 0.29315485, 0. , 0. ],

[ 0.78182313, 0.3828001 , 0. , 0. ]])

In []: make_square(A.T)

Out[]:

array([[ 0.76109774, 0.11810978, 0.54991376, 0.78182313],

[ 0.42980812, 0.59622975, 0.29315485, 0.3828001 ],

[ 0. , 0. , 0. , 0. ],

[ 0. , 0. , 0. , 0. ]])

will help you.

My 2 cents,

-eat

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