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Re: [Help-glpk] Modelling Advice Request - Project Tasks
From: |
jeff . kantor |
Subject: |
Re: [Help-glpk] Modelling Advice Request - Project Tasks |
Date: |
Thu, 21 Jan 2010 18:09:37 +0300 |
On Jan 21, 2010 9:30am, Andrew Makhorin <address@hidden> wrote:
> > On that subject, a member of this list has privately sent me a model
>
> > which does this.
>
>
>
> > Thanks to EVERYBODY who took the time to respond.
>
>
>
> > Here #39;s the new model, which uses a parameter for data input,
>
> > minimises the number of variables needed, and works very successfully:
>
>
>
> Mixed gomory cuts (i.e. glpsol --gomory) allows solving your new model
>
> with glpsol about 20 times faster than without using cuts.
>
>
>
> (Note that there are known more efficient formulations of the linear
>
> ordering problem.)
>
Indeed. Adding constraints to remove cycles from the solution space
reduces the time about another 30% at the cost of increased memory requirements.
I #39;m experimenting a bit right now, should
have an example model ready shortly.
Jeff
>
>
>
>
>
> _______________________________________________
>
> Help-glpk mailing list
>
> address@hidden
>
> http://lists.gnu.org/mailman/listinfo/help-glpk
>
On Jan 21, 2010 9:30am, Andrew Makhorin <address@hidden> wrote:
> > On that subject, a member of this list has privately sent me a model
>
> > which does this.
>
>
>
> > Thanks to EVERYBODY who took the time to respond.
>
>
>
> > Here's the new model, which uses a parameter for data input,
>
> > minimises the number of variables needed, and works very successfully:
>
>
>
> Mixed gomory cuts (i.e. glpsol --gomory) allows solving your new model
>
> with glpsol about 20 times faster than without using cuts.
>
>
>
> (Note that there are known more efficient formulations of the linear
>
> ordering problem.)
>
Indeed. Adding constraints to remove cycles from the solution space
reduces the time about another 30% at the cost of increased memory requirements.
I'm experimenting a bit right now, should
have an example model ready shortly.
Jeff
>
>
>
>
>
> _______________________________________________
>
> Help-glpk mailing list
>
> address@hidden
>
> http://lists.gnu.org/mailman/listinfo/help-glpk
>
Re: [Help-glpk] Modelling Advice Request - Project Tasks, Andrew Makhorin, 2010/01/20
Re: [Help-glpk] Modelling Advice Request - Project Tasks, Andrew Makhorin, 2010/01/20
Re: [Help-glpk] Modelling Advice Request - Project Tasks,
jeff . kantor <=
Re: [Help-glpk] Modelling Advice Request - Project Tasks, Andrew Makhorin, 2010/01/22
Re: [Help-glpk] Modelling Advice Request - Project Tasks, Jeffrey Kantor, 2010/01/25
Re: [Help-glpk] Modelling Advice Request - Project Tasks, Andrew Makhorin, 2010/01/26
Re: [Help-glpk] Modelling Advice Request - Project Tasks, Andrew Makhorin, 2010/01/26