[Coin-discuss] add a column at particular index

[Matthew Galati]

ok.

thanks,
matt


On Fri, 2009-06-05 at 15:13 -0400, Matthew Galati wrote:
> > Is there an OSI method for adding a column at a particular index? That
> > is, I want to add a column as the i-th column and shift all other
> > columns to the right.
>
> I don't think most (or any) optimizers that OSI supports include that
> functionality.  CPLEX doesn't, for example.  It would be quite expensive
> in general, and implementing it in OSI if it's not built into the solver
> lib is pretty horrendous--it involves unloading the problem, copying the
> problem or at least doing overlapping-memory moves of the data for the
> columns to the right of the insertion point, then reloading the problem
> in the solver.
>
> You're much better off just indirectly indexing columns through a vector
> that keeps them in the order you want.  (If I were to implement it in
> OSI, that's how I would do it.)  But for that, you are on your own.
>
>                Matt
>
> --
>                Matthew Saltzman
>
> Clemson University Math Sciences
> mjs AT clemson DOT edu
> http://www.math.clemson.edu/~mjs <http://www.math.clemson.edu/%7Emjs>
>
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