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Re: How to retrieve intermediate solutions of MIP problems without inter
Domingo Alvarez Duarte
Re: How to retrieve intermediate solutions of MIP problems without interrupting the solver?
Mon, 10 Aug 2020 11:31:00 +0200
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0
Hello Yuri !
Looking through the code I can see that the function
src/draft/glpios03.c::record_solution would be a good candidate to hook
a callback to do what you'll want, probably we'll also want a way to
signal to stop searching for more solutions based on the return value of
On 9/8/20 20:04, Yuri wrote:
For my problem Glpk quickly finds some solution and then goes on to
find better solutions and this takes a lot of time.
I'm interested in all solutions, beginning from the first integer
solution in finds.
I couldn't find a callback that is called when a better solution
For example, in this run it called glp_intopt which progressively
found 3 solutions, each better than the previous one:
Long-step dual simplex will be used
+ 633: mip = not found yet >= -inf (1; 0)
+ 1006: >>>>> 1.098691667e+01 >= 5.512339583e+00 49.8% (18; 0)
+ 4134: >>>>> 1.098525000e+01 >= 6.681520833e+00 39.2% (31; 22)
+ 7210: >>>>> 1.098458333e+01 >= 1.043275926e+01 5.0% (24; 87)
+ 7654: mip = 1.098458333e+01 >= tree is empty 0.0% (0; 195)
INTEGER OPTIMAL SOLUTION FOUND
I am looking for access to all of them as they become available.