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I tried to use qmip.cpp in Cbc/Samples (downloaded March 7) to solve a
simple quadratic 0-1 integer program (qmip1.mps) and got the following
solution:<br><br>
N0C0=N1C0=N2C0=N3C0=1 and min obj = 0<br><br>
This is not the minimum solution. Either N0C0=N1C0=N2C1=N3C1=1 or
N0C1=N1C1=N2C0=N3C1=1 will result in obj = -6<br><br>
Would you take a look at it and see what's gone wrong?<br><br>
As an experiment, I made the coefficient of the N0C0*N1C0 in the
objective function very large relative to other terms (see qmip2.mps),
preventing N0C0 and N1C0 from being 1 at the same time, qmip then
produced a correct answer: N0C1=N1C1=N2C0=N3C1=1 with obj = -6.<br><br>
<font face="Courier New, Courier">The variables are indexed as
below:<br>
0 N0C0<br>
1 N0C1<br>
2 N1C0<br>
3 N1C1<br>
4 N2C0<br>
5 N2C1<br>
6 N3C0<br>
7 N3C1<br>
<br>
</font>Thanks,<br><br>
Yiming<br><br>
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Yiming
Yao
<br>
Systems & Decision Sciences
Section yao3@llnl.gov
<br>
Lawrence Livermore National Laboratory Tel:
925-422-1922 <br>
7000 East Avenue, L-377<br>
Livermore, CA 94550<br>
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