Re: [Help-glpk] (no subject)

[Heinrich Schuchardt]

Hello Antonio,

if your matrix is sparse, keep the model sparse. In the rest of your 
model you would only waste memory and CPU time otherwise.

set A, dimen 3;
set I, dimen 2 := setof{(i,j,k) in A}(i,j);
param a{(i,j) in I} := sum{(i,j,k) in A} k;
display A, I, a;
data;
set A :=
  (1,1,1)
  (1,2,1)
  (1,3,1)
  (1,4,1)
  (2,6,1)
  (2,7,1)
  (2,8,1)
  (2,9,1)
  (2,10,1)
  (2,13,1)
  (2,15,1);
end;

Best regards

Heinrich Schuchardt



On 02.09.2013 22:29, Antonio Carlos Moretti wrote:
> How can I define a sparese matrix in GLPK.
> I am doing the following:
> ....
> param A{j in voos, i in seq}, default 0.0;
> param A:= [1,1] 1
> [1,2] 1
> [1,3] 1
> [1,4] 1
> [2,6] 1
> [2,7] 1
> [2,8] 1
> [2,9] 1
> [2,10] 1
> [2,13] 1
> [2,15] 1;
> ....
> Thanks ,
> Antonio
>
>
>
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