/prog/ - Matrix operations

Name: Anonymous 2008-09-15 18:19

def matrix_add(matrix1, matrix2):

    return [[el1 + el2 for el1, el2 in zip(row1, row2)] for row1, row2 in zip(matrix1, matrix2)]



def matrix_transpose(matrix):

    return list(zip(*matrix))



def matrix_multiply(matrix1, matrix2):

    matrix2_transposed = matrix_transpose(matrix2)

    return [[sum(x*y for x, y in zip(row, col)) for col in matrix2_transposed] for row in matrix1]

I would like to do these more elegantly and/or more efficiently. Any Haskellfags present?

Name: Anonymous 2008-09-15 18:50

row1, row2, fight the powah

Name: Anonymous 2008-09-15 19:10

>>2
gb2/pr/

Name: Anonymous 2008-09-15 19:29

import List



add = zipWith $ zipWith (+)

mul m1 m2 = map (\r -> map (foldl1 (+) . zipWith (*) r) $ transpose m2) m1

Name: Anonymous 2008-09-15 19:33

>>4
s/foldl1 (+)/sum/

Name: Anonymous 2008-09-15 21:49

: m+ [ [ + ] 2map ] 2map ;

: m* flip swap [ dupd [ [ * ] 2map sum ] curry map ] map nip ;

Name: Anonymous 2008-09-16 5:51

transpose = foldr (zipWith (:)) (repeat [])

Name: Anonymous 2008-09-16 6:19

Bitches don't know about my A+ (a dialect of APL).

Name: Anonymous 2008-09-16 11:57

>>8
Damn right, we don't. So, tell us about them apples...

Name: Anonymous 2008-09-16 12:07

(″･ิ_･ิ)っ-̾

Fuck you.

Name: Anonymous 2008-09-16 12:07

(″･ิ_･ิ)っ-̾
Fuck you.

Name: Anonymous 2008-09-16 12:08

>>10
( ･_･) /dqn/ is that way ---->

Name: Anonymous 2008-09-16 12:09



(″･ิ_･ิ)っ-̾

Fuck you.

Name: Anonymous 2008-09-16 12:09

>>12
Why won't that crap work here?

Name: Anonymous 2008-09-16 12:10

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Name: Anonymous 2008-09-16 12:11

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Name: Anonymous 2008-09-16 12:27

this is not /dqn/

Name: Anonymous 2008-09-16 13:24

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Name: Anonymous 2008-09-16 14:02

this is not /dqn/

Name: Anonymous 2010-11-14 21:42

Name: Anonymous 2010-12-25 0:15

Don't change these.

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Entire Thread Thread List

Matrix operations

1 Name: Anonymous 2008-09-15 18:19

2 Name: Anonymous 2008-09-15 18:50

3 Name: Anonymous 2008-09-15 19:10

4 Name: Anonymous 2008-09-15 19:29

5 Name: Anonymous 2008-09-15 19:33

6 Name: Anonymous 2008-09-15 21:49

7 Name: Anonymous 2008-09-16 5:51

8 Name: Anonymous 2008-09-16 6:19

9 Name: Anonymous 2008-09-16 11:57

10 Name: Anonymous 2008-09-16 12:07

11 Name: Anonymous 2008-09-16 12:07

12 Name: Anonymous 2008-09-16 12:08

13 Name: Anonymous 2008-09-16 12:09

14 Name: Anonymous 2008-09-16 12:09

15 Name: Anonymous 2008-09-16 12:10

16 Name: Anonymous 2008-09-16 12:11

17 Name: Anonymous 2008-09-16 12:27

18 Name: Anonymous 2008-09-16 13:24

19 Name: Anonymous 2008-09-16 14:02

20 Name: Anonymous 2010-11-14 21:42

23 Name: Anonymous 2010-12-25 0:15

Name: Anonymous 2008-09-15 18:19

Name: Anonymous 2008-09-15 18:50

Name: Anonymous 2008-09-15 19:10

Name: Anonymous 2008-09-15 19:29

Name: Anonymous 2008-09-15 19:33

Name: Anonymous 2008-09-15 21:49

Name: Anonymous 2008-09-16 5:51

Name: Anonymous 2008-09-16 6:19

Name: Anonymous 2008-09-16 11:57

Name: Anonymous 2008-09-16 12:07

Name: Anonymous 2008-09-16 12:07

Name: Anonymous 2008-09-16 12:08

Name: Anonymous 2008-09-16 12:09

Name: Anonymous 2008-09-16 12:09

Name: Anonymous 2008-09-16 12:10

Name: Anonymous 2008-09-16 12:11

Name: Anonymous 2008-09-16 12:27

Name: Anonymous 2008-09-16 13:24

Name: Anonymous 2008-09-16 14:02

Name: Anonymous 2010-11-14 21:42

Name: Anonymous 2010-12-25 0:15