Thanks for the tips, I'll have a look. Hugo
On Fri, Apr 11, 2014 at 11:53 AM, Nathann Cohen <[email protected]>wrote: > Hello Hugo ! > > I see, then perhaps this parameter from GLPK has no effect for such short > times. Did you check whether they know that it should only be set for > longer times, I.e. is it mentioned somewhere in their documentation ? > > I am answering your message with a mobile phone right now, unfortunately I > have no working computer at the moment :-) > > I do not know how you can access the "best solution it found" at that > time, if getting the answers with the "get_values" method does not work. It > depends on the internals of GLPK, and perhaps they do not store the best > solution when the computations ended because of the time limit. If you need > a temporary workaround, maybe you can try to set an approximation ratio > instead of a time limit : the process will stop once the solver has found a > solution which is not too far away from the optimal one, and in this case I > remember that the solution can be accessed. > > Well. I cannot do much at the moment without a computer, but the key to > that is probably in the interface between Sage and GLPK, and possibly not > very hard to solve : if GLPK has the feature, it can usually be exposed in > Sage very quickly. Try to take a look at file > sage/numerical/backends/glpk_backend.pyx, this is where everything happens > and maybe you can solve your problem. And please submit a patch to Sage if > you find the key to it, this would definitely be useful to others. Have > fuuuuuun !!!! Nathann > > On Wednesday, 9 April 2014, Hugo Monteiro <[email protected]> > wrote: > >> Hi, >> >> Thank you for getting back to me. >> it seems the problem lies in me using too small times. If I increase it >> to a few minutes, instead of a few seconds, it then interrupts computation >> as expected (although I still have to use the timelimit parameter, as the >> timelimit_intopt still gives an error) >> >> My problem now is that I don't know how to access the best valid solution >> it managed to find within the time it ran. >> >> How do you suggest I should proceed? >> >> Hugo >> >> >> On Tue, Apr 8, 2014 at 1:27 PM, Nathann Cohen <[email protected]>wrote: >> >>> Helloooooooooo !! >>> >>> I am trying to use the interface to use the Mixed Integer Programming >>>> features in Sage. One of the things I would like to do is to limit the >>>> execution time to a certain number of seconds and return the current best >>>> valid solution. >>>> >>> >>> This should be possible. >>> >>> >>>> When setting the timelimit parameter to 10 seconds for example and >>>> checking the value of the parameter afterwards, I can see it has been >>>> updated, but the program execution ignores the setting and just keeps >>>> running for a long time. >>>> I tried setting instead to set the timelimit_intopt parameter to 10000, >>>> but when I do this, I get "ValueError: This parameter is not available." >>>> I went to the code to check I was using the correct string and I see >>>> nothing wrong. >>>> >>>> Can someone point me in the right direction? >>>> >>> >>> Can you give a shortest possible example of code that produces this >>> problem ? >>> >>> Nathann >>> >>> -- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "sage-support" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/sage-support/F8dWJ_w3Mtg/unsubscribe. >>> To unsubscribe from this group and all its topics, send an email to >>> [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at http://groups.google.com/group/sage-support. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "sage-support" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/sage-support/F8dWJ_w3Mtg/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/sage-support. >> For more options, visit https://groups.google.com/d/optout. >> > -- > You received this message because you are subscribed to a topic in the > Google Groups "sage-support" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/sage-support/F8dWJ_w3Mtg/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/sage-support. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sage-support" group. 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