[PPL-devel] [GIT] ppl/ppl(master): Added a workaround to a space efficiency bug affecting MIP_Problem.

[Enea Zaffanella]

Module: ppl/ppl
Branch: master
Commit: 96604c0b36129ddc2ab6079a11c3babfb4dc69cd
URL:    http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=96604c0b36129ddc2ab6079a11c3babfb4dc69cd

Author: Enea Zaffanella <zaffanella at cs.unipr.it>
Date:   Sun Dec 19 12:05:02 2010 +0100

Added a workaround to a space efficiency bug affecting MIP_Problem.
The baseline patch has been contributed by Marco Poletti.

MIP_Problem now stores the input constraints as a sequence of Constraint*.
In this sequence, we distinguish between owned constraints (whose resources
are under control of the current MIP_Problem object) and inherited constraints
(whose resources are shared with, and owned by, another MIP_Problem object).
When starting a branch-and-bound computation looking for an integral
feasible/optimal solution, we now inherit (rather than copy) the input
constraints.

The workaround greatly improves space/time efficiency on (mixed) integral
problems, also providing a (simple and reasonable) partial solution to

    https://www.cs.unipr.it/mantis/view.php?id=62

The solution is still partial: a complete solution requires the implementation
of a backtracking mechanism for incrementally added constraints.

---

 src/MIP_Problem.cc           |   78 +++++++++++++++++-----
 src/MIP_Problem.defs.hh      |   90 ++++++++++++++++++++++++--
 src/MIP_Problem.inlines.hh   |  147 ++++++++++++++++++++++++++++++++++++++++--
 src/MIP_Problem.templates.hh |    6 +-
 4 files changed, 288 insertions(+), 33 deletions(-)

Diff:   http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commitdiff;h=96604c0b36129ddc2ab6079a11c3babfb4dc69cd