Re: [sage-support] Re: Making a copy of a MixedIntegerLinearProgram

2012-05-15 Thread Emil
Hi Nathann,

Thanks for writing the MILP class - it works very well. Now, I can do:

x = lp.new_variable()

Is there any way to do something like

x = lp.get_existing_variables()

?

I'm working on some graph theoretic stuff: I'm solving two LPs for
each graph, for as many graphs as I can. - Emil.



On 15 May 2012 08:00, Nathann Cohen nathann.co...@gmail.com wrote:
 By the way, could I ask you what lead you to create and solve many LP ? I
 mean, what are you solving which requires you to do that ? ^^;

 Nathann

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Re: [sage-support] Re: Making a copy of a MixedIntegerLinearProgram

2012-05-15 Thread Emil
Next issue is that the Gurobi backend doesn't support the copy:

AttributeError: 'sage.numerical.backends.gurobi_backend.GurobiBacke'
object has no attribute 'copy'

Any idea how much work this would be to do?

(I can now do what I wanted to do before, at least with GLPK.)

Emil

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Re: [sage-support] Re: Making a copy of a MixedIntegerLinearProgram

2012-05-15 Thread Nathann Cohen
Hellooo !!

 Next issue is that the Gurobi backend doesn't support the copy:

Oops ^^;

 Any idea how much work this would be to do?

Oh, it's usually quite straightforward to implement such things.
Usually the feature already exists in the solver's C api, and all the
work that needs to be done is to expose it in Sage :-)

Nathann

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Re: [sage-support] Re: Making a copy of a MixedIntegerLinearProgram

2012-05-15 Thread Emil
OK I'll take a look :)

On 15 May 2012 21:55, Nathann Cohen nathann.co...@gmail.com wrote:
 Hell Emil !!

 Any chance you could make a patch? :)   (I'd volunteer myself, but I
 would probably mess it up!)

 H I could, but this patch is so local that it really is an
 ideal occasion to write your first patch... Are you sure you do not
 want to give it a try ? It is fun to be a developper, you will feel
 like Sage becomes your home directory, and everybody will throw rocks
 at you you create new bugs.. And all all the while you will be
 having fun :-D

 Nathann

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