#11606: simplify constraints in linear programs
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Reporter: john_perry | Owner: ncohen
Type: enhancement | Status: needs_info
Priority: major | Milestone: sage-4.7.2
Component: linear programming | Keywords: sd32
Work_issues: | Upstream: N/A
Reviewer: | Author: john_perry
Merged: | Dependencies:
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Comment(by john_perry):
Replying to [comment:22 ncohen]:
> Well, the current documentation of the __init__ method of the
MixedIntegerLinearProgram class also appears just before, in the section's
documentation (and that appears in the doc). But you are right : it's
probably best to remove it just to avoid later mistakes.
>
> Actually, it should just contain the line "Constructor" and the
doctests.
Will do.
> > This strikes me as a matter best left to the client: the normalization
shouldn't choose the type of the coefficients of the constraints
>
> You are right in general, though in this special situation the answer
has been taken from us. When a constraint is added, it is forwarded to the
solver backend which is the only place where it is saved. Now, all of
CPLEX/GLPK/Coin only accept floats as data. As mip.pyx is a Cython file,
the best is probably to deal with float variables.
Are you saying I should coerce everything to floats, or leave it be? I
thought to leave it be in case some future back end accepted rationals;
the backends can do their own coercion.
> By the way, why do you create so many lists ?
You seem to think I know something about proper P/Cython programming.
`:-)` Thanks for the suggestion; that will help speed things up a bit,
though I think my real problem lies elsewhere.
> Sorry about the delay again. I'm getting back to the point where I can
deal with tasks on-the-fly, and not with the ones that should have been
settled the week before :-)
No problem. I'm in a bit of a fix myself, so it may take a few days before
another patch is ready, anyway.
By the way, do you know what those colored balls next to "opened: ...
weeks ago" mean?
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11606#comment:23>
Sage <http://www.sagemath.org>
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