[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re[4]: [Help-glpk] glpk 4.5 release information
From: |
Michael Hennebry |
Subject: |
Re[4]: [Help-glpk] glpk 4.5 release information |
Date: |
Wed, 21 Jul 2004 09:32:08 -0500 (CDT) |
On Wed, 21 Jul 2004, Andrew Makhorin wrote:
> >I am very interested in this, if you have the time.
>
> You should modify the file glpmip2.c as follows:
>
> 881 /* check if the time limit has been exhausted */
> 882 if (tree->tm_lim >= 0.0 && tree->tm_lim <= utime() - tree->tm_beg)
> 883 { if (tree->msg_lev >= 3)
> 884 print("Time limit exceeded; search terminated");
> 885 ret = MIP_E_TMLIM;
> 886 goto done;
> 887 }
> /* additional termination tests should go here */
> if (tree->found && tree->best <= desired_value)
> { print something, if needed;
> ret = MIP_E_TMLIM;
Why not a value indicating OK?
> goto done;
> }
> 888 /* display current progress of the search */
My recollection is that there is a parameter
that would do almost exactly what was requested.
At one time it was called LPX_K_TOLOBJ.
An upper bound of 10**-3 was enforced.
Editing the code to raise that bound should
allow the user to specify a 10% rule.
I gathered from reading the code that it was intended to
deal with the vagaries of finite precision arithmetic,
but it should allow one to settle for a not quite optimum.
Of course the method specified is a bit more flexible.
> tree->found is a flag which being set indicates that at least one
> integer feasible solution has been found.
>
> tree->best is the objective value for the best known integer feasible
> solution (it is undefined if the flag tree->found is not set).
>
> If you need to know the current global bound, it can be obtained as
> follows:
>
> { int r = mip_pseudo_root(tree);
> insist(r != 0);
> insist(tree->slot[r].node != NULL);
> global_bound = tree->slot[r].bound;
> ...
> }
--
Mike address@hidden
"Nothing says it like words if you know how to use them."
-- the Professional Organization of English Majors
- [Help-glpk] glpk 4.5 release information, Andrew Makhorin, 2004/07/19
- Re: [Help-glpk] glpk 4.5 release information, Philip Warner, 2004/07/19
- Re[2]: [Help-glpk] glpk 4.5 release information, Andrew Makhorin, 2004/07/19
- Re[2]: [Help-glpk] glpk 4.5 release information, Philip Warner, 2004/07/20
- Re[3]: [Help-glpk] glpk 4.5 release information, Andrew Makhorin, 2004/07/21
- Re[3]: [Help-glpk] glpk 4.5 release information, Philip Warner, 2004/07/21
- Re[4]: [Help-glpk] glpk 4.5 release information, Andrew Makhorin, 2004/07/21
- Re[4]: [Help-glpk] glpk 4.5 release information,
Michael Hennebry <=
- Re[5]: [Help-glpk] glpk 4.5 release information, Andrew Makhorin, 2004/07/21
- Re[5]: [Help-glpk] glpk 4.5 release information, Michael Hennebry, 2004/07/21
- Re[6]: [Help-glpk] glpk 4.5 release information, Andrew Makhorin, 2004/07/21