Re: [Fwd: GLPK doubt]
Michael Hennebry <[email protected]> Fri, 16 Feb 2024 13:07:01 -0600 (CST)
| Newsgroups | gmane.comp.gnu.glpk |
|---|---|
| Message-ID | <[email protected]> |
This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. ---2121900931-960175813-1708110421=:7686 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8BIT On Thu, 8 Feb 2024, Manuel Muñoz Márquez wrote: > You have a decision problem if and only if you have decision variables. I think OP is using "decision variables" in a non-standard way: binary auxilliary variables representing choices, e.g., project p is done in month m. OP wants to reduce it to one variable per project. It won't work. If q[p]=1 represents project p is done in month 1 and q[p]=37 represents project p is done in month 37, then q[p]=19=(1+37)/2 allows project p to be half done in month 1 half in month 37. OP could get it down to 6 binary variables per project, but 'tain't obvious that it would help. The LP relaxation might not be as tight. The traditional TSP formulation has n*(n-1)/2 binary variables. It could be got down to 2*n*lg(n), but so far as I know, no one has tried to deal with the mess. My suspicion is that OP's problem is equivalent to an assignment problem. In that case, 12000 variables should not be difficult. -- Michael [email protected] "SCSI is NOT magic. There are *fundamental technical reasons* why it is necessary to sacrifice a young goat to your SCSI chain now and then." -- John Woods ---2121900931-960175813-1708110421=:7686--