
From:  Alessandro Urbano 
Subject:  [Helpglpk] need help on matrix multiplication 
Date:  Wed, 19 Aug 2009 07:31:18 +0000 
I had some trouble on creating a matrix multiplication. This is what I wrote s.t. Costraint1{l in A,d in B} : sum{j in C} D[l,j] * E[j,d] <= 13; I try to find some documentation on internet and I've found that is not that the correct way to implement matrix multiplication.I've found this: >>> how can I mutiply a m*n matrix (A) by a n*1 matrix(B)? Given, say, param A {1..m, 1..n}; param B {1..n}; you can write: sum {j in 1..n} A[i,j] * B[j] to get the ith element of A times B. There is no "matrix multiplication" operator in AMPL that would let you write simply "A * B", however. >>> I know that gmpl is a subset of AMPL ,then if I don't find an instruction to do this operation in AMPL,surely I don't find that instruction in gmpl (i think so,even some difference that I don't know) Screensaver e Sfondi: personalizza il tuo PC con Messenger! 
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