[Coin-lpsolver] CLP features

[Michal.Kaut at tietoenator.com]

Hello,
 
Our company needs an LP solver for our optimization problem, and is
considering CLP as one of the alternatives. We have, however, some
special requirements, so we need to know whether CLP satisfies them (or,
how big changes we would have to make in order to satisfy them). I will
be grateful for any answers, tips, and/or comments:

So, here is the list:

- Is it possible to enforce certain basis changes violating
non-negativity of some basic variables, with a return phase afterwards
that restores the non-negativity in a fast way with high priority?
- Is it possible to specify, for each iteration, a subset of non-basic
variables, from which the new variable entering the basis is chosen?
- Is it possible to provide a procedure that decides whether a non-basic
variable is wanted as a candidate for entering the basis or not?
- Is it possible to restrict basis changes of piecewise linear variables
? Example: a difference between a production and the demand is modelled
by variables y_1, y_2..., with increasing costs c_1, c_2,... Is it
possible to limit the corresponding basis changes e.g. only into a
positive direction, i.e. y_i can only be replaced by y_j, j>i ?


Thanks a lot in advance.
 
Regards,
 
Michal Kaut
Tieto Enator