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## Re: [Bug-glpk] GLPSOL outputs MIP solution that is not LP optimal for fi

**From**: |
xypron |

**Subject**: |
Re: [Bug-glpk] GLPSOL outputs MIP solution that is not LP optimal for fixed integers |

**Date**: |
Sun, 13 Sep 2009 23:10:05 -0700 (PDT) |

Andrew Makhorin wrote:
>* *
>*> I would not have expected a MIP solution to yield an noninteger*
>*> objective for this model.*
>* *
>* 'incommon' is declared as continuous:*
>* *
>* var incommon {i in teams, j in teams: i < j}, >=0, <=1;*
>* *
>* so I do not see a problem. Why do you think that all components of*
>* 'incommon' must be integral?*
>* *
Hello Andrew,
the feasibility pump provides assumedly feasible solution where all
binaries are either 0 or 1.
If I fix the values of the binaries and resolve the original problem
all components are integral.
Please, run the files
http://www.nabble.com/file/p25430771/f1.mod f1.mod
http://www.nabble.com/file/p25430771/f2.mod f2.mod
(Please, check the ODBC connection data or use CSV.)
glpsol.exe --fpump --tmlim 30 -m f1.mod
glpsol.exe -m f2.mod
Compare the objective
f1: 1.041490000e+002
f2: 1.08
f1 saves the binary vlaues from the feasibility pump to the database.
f2 uses this values as fixed values.
Best regards
Xypron
--
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