[Bug-glpk] Re: Bug with GLPK/glpkmex

[Ali Ozer Ercan]

Hi,

Please ignore my previous mail. I found the bug. It is with the Matlab
interface, not with glpk itself.

Ali.

On Mon, Nov 17, 2008 at 3:28 PM, Ali Ozer Ercan <address@hidden> wrote:
> Hi,
>
> I am using GLPK with matlab (with the glpkmex extension) and I found a
> bug. Please extract the attached tarball and run glpk_fail_example.m
> in Matlab (you need glpkmex, the interface to Matlab). It is a simple
> routing optimization. The first plot shows the possible links between
> nodes and the numbers (in blue) on the links show the capacity in
> Mbps. The flows are 18Mbps so the routes cannot use the links with
> 12Mbps capacity. This translates to an upper bound constraint in GLPK.
> I solve the problem with both GLPK and Matlab's 'bintprog'. The
> bintprog gives the right solution (last 3 plots) while the solution
> given by GLPK (plots 2, 3 and 4) do use the links with 12 Mbps
> capacity, which means the UB constaint is violated. This is also
> detected by the lines 42--45 of solve_opt.m. The warning is executed
> if the ub constraint is violated, and the exit status of glpk is 5.
>
> I don't know if this is a problem of GLPK or glpkmex, but since
> glpkmex is just a Matlab interface to GLPK and it is GLPK who is
> performing the optimization, I thought this is probably GLPK's bug.
>
> Best,
>
> Ali Ercan.
>
> --
> +++++++++++++++++++++++++++++++++++
> Ali Ozer Ercan
> Post Doctoral Researcher
> Berkeley Wireless Research Center
> 2108 Allston Way, Suite 200
> Berkeley, CA 94704-1302 USA
> http://www.eecs.berkeley.edu/~aliercan
> +++++++++++++++++++++++++++++++++++
>



-- 
+++++++++++++++++++++++++++++++++++
Ali Ozer Ercan
Post Doctoral Researcher
Berkeley Wireless Research Center
2108 Allston Way, Suite 200
Berkeley, CA 94704-1302 USA
http://www.eecs.berkeley.edu/~aliercan
+++++++++++++++++++++++++++++++++++