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Re: [Help-glpk] Initial starting point of simplex algorithm
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From: |
Andrew Makhorin |
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Subject: |
Re: [Help-glpk] Initial starting point of simplex algorithm |
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Date: |
Thu, 24 Jan 2013 17:40:34 +0400 |
> PS: here is a small log of both problems
>
> GLPK Simplex Optimizer, v4.47
> 191255 rows, 68860 columns, 450946 non-zeros
> 0: obj = 0.000000000e+000 infeas = 5.436e+009 (28783)
> ...
> 17761: obj = -8.927238865e+008 infeas = 2.030e+007 (14520)
> PROBLEM HAS NO FEASIBLE SOLUTION
>
> Elasticity
> Addtional constraints 220038 for 191255 rows
> Current column size is 68860
> Additional Constraints 220038
> Current column size after resize is 288898
> GLPK Simplex Optimizer, v4.47
> 191255 rows, 288898 columns, 642201 non-zeros
> 0: obj = 0.000000000e+000 infeas = 5.436e+009 (28783)
> ...
> * 1552: obj = 0.000000000e+000 infeas = 1.490e-008 (28782)
> OPTIMAL SOLUTION FOUND
> Sinf is 0
BTW, in the second case the objective (Sinf, I guess) is zero on all
iterations. Probably you forgot to assign objective coefficients to
elastic variables.