matrix Multiplication
David
71david at libero.it
Wed Oct 18 14:51:16 CEST 2006
Il 18 Oct 2006 04:17:29 -0700, Sssasss ha scritto:
> hi evrybody!
>
> I wan't to multiply two square matrixes, and i don't understand why it
> doesn't work.
Can I suggest a little bit less cumbersome algorithm?
def multmat2(A,B):
"A*B"
if len(A)!=len(B): return "error" # this check is not enough!
n = range(len(A))
C = []
for i in n:
C.append([0]*len(A)) # add a row to C
for j in n:
a = A[i] # get row i from A
b = [row[j] for row in B] # get col j from B
C[i][j] = sum([x*y for x,y in zip(a,b)])
return C
regards
D.
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