Re: [Tutor] How to sum rows and columns of a matrix?

[Pierre Barbier de Reuille]

Even better :
import numarray
m = numarray.arange(16,shape=(4,4))
numarray.sum(m)
array([24, 28, 32, 36])
numarray.sum(axis=1)
array([ 6, 22, 38, 54])
Pierre
Kent Johnson a écrit :
Kent Johnson wrote:
Liam Clarke wrote:
There's a specific package for arrays
http://www.stsci.edu/resources/software_hardware/numarray
that implements array mathematics. I use it for pixel map manipulation
in pygame, so it's relatively fast.

Here is one way to do what you want using numarray:

Here is another way, probably more idiomatic and faster. (I'm just 
doodling with numarray so there may still be a better way to do this...)

 >>> import numarray
 >>> m=numarray.array(range(16),shape=(4,4))
 >>> numarray.add.reduce(m)
array([24, 28, 32, 36])
 >>> numarray.add.reduce(m, axis=1)
array([ 6, 22, 38, 54])
Kent

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