Thanks guys, all these are very interesting. I get down to work. Thanks again.
2016-02-09 1:08 GMT+02:00 Chris Matrakidis <cmatr...@gmail.com>: > Should I suppose that the answer to my question is negative, i.e. it is >> not possible to force GLPK to start searching from a particular point? >> > > Since you are using MathProg, you can duplicate the objective function as > a constraint and specify the value you obtained with your heuristic as an > upper limit (I'm assuming you are minimising). This way the search will not > investigate nodes with higher objective values, saving time, effectively > duplicating what would happen if the solver found the solution on its own. > However this may make each iteration slower, depending on the structure of > your problem. Also note that the solver output will not indicate the > correct gap until a new solution is found. > > Nevertheless, I mast say that I have no idea about what --cuts, --pcost, >> --proxy, --mir and --mipgap 0.2 mean or stand for. >> Could any one inform me in a few words about the meaning of all these? Or >> better, is there any text explaining all these? >> > > Some further info in addition to what Noli sent: > --pcost enables "pseudocost branching with strong branching > initialisation". A google search with the quoted sentence will find lots of > additional information. > --cuts enables all the implemented cut families, so --mir is redundant. > Cuts are constraints added during the search that remove non integer > solutions (like the current lp relaxation). > --mipgap 0.2 instructs the solver to stop when the best solution found is > within 20% of the lower (or upper) limit. Therefore the solution is certain > to be at most 20% off the optimum. > > > Best Regards, > > Chris Matrakidis > -- Ioannis X. Tassopoulos
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