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## Re: [Help-glpk] Solution not found on larger problem

**From**: |
Andrew Makhorin |

**Subject**: |
Re: [Help-glpk] Solution not found on larger problem |

**Date**: |
Sun, 11 Sep 2011 23:30:30 +0400 |

>* thx for the fast reply.*
>* I'll use an time threshold then and be happy with what I get.*
>* *
>* Is there anything on the glpk todo-list that might fix the problem in *
>* the (near) future?!*
Chris, enlight13.mps violates the following mps standard conventions:
1) it uses LI bound type, which is non-standard;
2) the standard says that "for integer variables, the default bounds on
columns are 0 and 1". Enlight13.mps does not set upper bounds for some
columns (LI sets only lower bounds), so such columns are considered as
binary that leads to incorrect results.
For more details about the mps format please see:
http://www.cenapad.unicamp.br/parque/manuais/OSL/oslweb/features/featur11.htm
in particular, the topic "BOUNDS section". Thanks.
Andrew Makhorin