[Osi] [Clp] set row solution (activities)

Matthew Galati magh at lehigh.edu
Thu Aug 13 18:45:46 EDT 2009


True. That's a design question.

In fact there is a note in OsiCpx that says you must set both concurrently
as of CPX7.

Ok - then I need setColSolution to update rowActivity_ itself, or, overload
setColSolution to accept a col and row solution. Basically, I just need some
way to set row activities - so that when a CGL is called (like MIR) and asks
for row activities, it gets back the correct value.


The row activity is determined by the column solution, so how could it
> make sense to set it independently?
>
> Ted
>
> 2009/8/13 Matthew Galati <magh at lehigh.edu>:
> > Why not just add a method to ClpModel that sets rowActivity_ and then a
> method to OsiClp that sets row solution?
> >
> >
> >
> >> Disgusting solution but you could create a class that inherits from
> clpsimplex, provides functions to set rowactivity (protected) and cast to
> it.
> >>
> >>
> >>
> >> From: clp-bounces at list.coin-or.org [mailto:clp-bounces at list.coin-or.org]
> On Behalf Of Matthew Galati
> >> Sent: Thursday, August 13, 2009 5:14 PM
> >> To: Lou Hafer
> >> Cc: osi at list.coin-or.org; clp at list.coin-or.org
> >> Subject: Re: [Clp] [Osi] set row solution (activities)
> >>
> >>
> >>
> >> I think setRowPrice sets the dual solution - not the (primal) row
> solution.
> >>
> >> Internally, it is the rowActivity_ array that needs to be set - that is
> what is returned by getRowActivity(). That is why you are not seeing it come
> back - you are actually setting the duals with setRowPrice.
> >>
> >> I am not sure what it does to internals, but I think all you need is a
> method "setRowSolution" and do a memcpy into rowActivity_.
> >>
> >>
> >>
> >>
> >> Matt,
> >>
> >>        Osi.setColSolution and Osi.setRowPrice will set the column and
> row
> >> solution, respectively.  Row activity should follow from setColSolution.
> >>
> >>        Based on the Osi unit test, OsiClp ignores imposed row and column
> >> solutions (at least, they are not immediately reflected in the results
> returned
> >> for row activity and reduced costs).
> >>
> >>                                                Lou
> >>
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> >>
> >>
> >
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> >
>
>
>
> --
> Dr. Ted Ralphs
> Associate Professor, Lehigh University
> (610) 628-1280
> ted 'at' lehigh 'dot' edu
> coral.ie.lehigh.edu/~ted <http://coral.ie.lehigh.edu/%7Eted>
>
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