[Numpy-discussion] Matrix Class
Sebastian Berg
sebastian at sipsolutions.net
Wed Feb 11 10:47:54 EST 2015
On Di, 2015-02-10 at 15:07 -0700, cjw wrote:
> It seems to be agreed that there are weaknesses in the existing Numpy Matrix
> Class.
>
> Some problems are illustrated below.
>
Not to delve deeply into a discussion, but unfortunately, there seem far
more fundamental problems because of the always 2-D thing and the simple
fact that matrix is more of a second class citizen in numpy (or in other
words a lot of this is just the general fact that it is an ndarray
subclass).
I think some of these issues were summarized in the discussion about the
@ operator. I am not saying that a matrix class separate from numpy
cannot solve these, but within numpy it seems hard.
> I'll try to put some suggestions over the coming weeks and would appreciate
> comments.
>
> Colin W.
>
> Test Script:
>
> if __name__ == '__main__':
> a= mat([4, 5, 6]) # Good
> print('a: ', a)
> b= mat([4, '5', 6]) # Not the expected result
> print('b: ', b)
> c= mat([[4, 5, 6], [7, 8]]) # Wrongly accepted as rectangular
> print('c: ', c)
> d= mat([[1, 2, 3]])
> try:
> d[0, 1]= 'b' # Correctly flagged, not numeric
> except ValueError:
> print("d[0, 1]= 'b' # Correctly flagged, not numeric", '
> ValueError')
> print('d: ', d)
>
> Result:
>
> *** Python 2.7.9 (default, Dec 10 2014, 12:28:03) [MSC v.1500 64 bit
> (AMD64)] on win32. ***
> >>>
> a: [[4 5 6]]
> b: [['4' '5' '6']]
> c: [[[4, 5, 6] [7, 8]]]
> d[0, 1]= 'b' # Correctly flagged, not numeric ValueError
> d: [[1 2 3]]
> >>>
>
>
>
>
>
> --
> View this message in context: http://numpy-discussion.10968.n7.nabble.com/Matrix-Class-tp39719.html
> Sent from the Numpy-discussion mailing list archive at Nabble.com.
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