<br><font size=2 face="sans-serif">Hold it -- there's distinction here
that should be made (or a hair splitting, depending on your point of view).
</font>
<br>
<br><font size=2 face="sans-serif">IPOPT is available free of charge for
*everyone* -- academics/nonacademics alike. IPOPT is available under
an open-source license -- one that it is approved as meeting the "open
source definition" (OSD). The OSD doesn't allow discriminate
by user -- hence any license that is "for academics only" is
not "open source". </font>
<br>
<br><font size=2 face="sans-serif">IPOPT developers were able to design
their code so that the components/functions they are dependent on (and
didn't write) can be down-loaded separately (e.g., under their own licensing
agreements). </font>
<br>
<br><font size=2 face="sans-serif">To use IPOPT with HSL -- that
*combination*is like SCIP. But IPOPT itself is true open-source.
(Q: Doesn't IPOPT's design allow you to use anything thing that performs
the same function as the HSL?)</font>
<br>
<br><font size=2 face="sans-serif">If the reason the SCIP owners use the
ZIB-license is becuase some component used by SCIP is under the ZIB license,
then may be able to do something like IPOPT did -- but I don't know the
reasons for their licensing decision. </font>
<br>
<br><font size=2 face="sans-serif">I think it'd be great to have SCIP open
and on COIN-OR -- but be that as it may, it's still great they made it
possible to use it with the open COIN LP solver, CLP and are sharing it
with the academic community. </font>
<br>
<br><font size=2 face="sans-serif">Robin</font>
<br><font size=2 face="sans-serif"><br>
----------------------------------------------------------------------------------<br>
Robin Lougee-Heimer<br>
IBM TJ Watson Research Center<br>
1101 Kitchawan Road, Yorktown Heights, NY 10598<br>
ph: 914-945-3032 fax: 914-945-3434 <br>
robinlh@us.ibm.com<br>
http://www.coin-or.org<br>
<br>
</font>
<br>
<br>
<br>
<table width=100%>
<tr valign=top>
<td width=40%><font size=1 face="sans-serif"><b>Carl Wilburn <csw_iii@yahoo.com></b>
</font>
<br><font size=1 face="sans-serif">Sent by: coin-discuss-bounces@list.coin-or.org</font>
<p><font size=1 face="sans-serif">09/21/2005 01:01 PM</font>
<table border>
<tr valign=top>
<td bgcolor=white>
<div align=center><font size=1 face="sans-serif">Please respond to<br>
Discussions about open source software for Operations Research
</font></div></table>
<br>
<td width=59%>
<table width=100%>
<tr>
<td>
<div align=right><font size=1 face="sans-serif">To</font></div>
<td valign=top><font size=1 face="sans-serif">coin-discuss@list.coin-or.org</font>
<tr>
<td>
<div align=right><font size=1 face="sans-serif">cc</font></div>
<td valign=top>
<tr>
<td>
<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td valign=top><font size=1 face="sans-serif">[Coin-discuss] SCIP: an open-source
Constraint Mixed Integer Programming
Solver (Tobias Achterberg)</font></table>
<br>
<table>
<tr valign=top>
<td>
<td></table>
<br></table>
<br>
<br>
<br><font size=2><tt><br>
The availability of SCIP sounds similar to IPOPT.<br>
IPOPT is available free of charge for<br>
academic/non-commercial use. It does, however, make<br>
use of subroutines from the HSL which are again, free<br>
for academic/non-commercial use but require a fee for<br>
commercial use. <br>
<br>
Someone correct me if I'm wrong, but SCIP could be<br>
made available thru COIN in a similar fashion.<br>
<br>
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> Today's Topics:<br>
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> 1. SCIP: an open-source Constraint Mixed Integer<br>
> Programming<br>
> Solver (Tobias Achterberg)<br>
> <br>
> <br>
><br>
----------------------------------------------------------------------<br>
> <br>
> Message: 1<br>
> Date: Wed, 21 Sep 2005 13:04:47 +0200<br>
> From: Tobias Achterberg <achterberg@zib.de><br>
> Subject: [Coin-discuss] SCIP: an open-source<br>
> Constraint Mixed Integer<br>
> Programming
Solver<br>
> To: coin-discuss <coin-discuss@list.coin-or.org><br>
> Message-ID: <43313E4F.8010806@zib.de><br>
> Content-Type: text/plain; charset=us-ascii<br>
> <br>
> Dear colleagues,<br>
> <br>
> the following announcement has only limited relation<br>
> to the COIN project, but if you are looking for<br>
> open-source software for Mixed Integer Programming,<br>
> you might be interested. However, if you think<br>
> the COIN LP solver of John Forrest is a greate piece<br>
> of software (which is true), you have another<br>
> opportunity to bring it to good use by using SCIP<br>
> linked to CLP.<br>
> <br>
> =====<br>
> <br>
> I'd like to announce the release of SCIP (Solving<br>
> Constraint Integer Programs).<br>
> SCIP is a framework for Constraint Integer<br>
> Programming oriented towards the needs<br>
> of Mathematical Programming experts who want to have<br>
> total control of the<br>
> solution process and access detailed information<br>
> down to the guts of the solver.<br>
> It integrates techniques from Mixed Integer<br>
> Programming, Constraint Programming<br>
> and SAT Solving.<br>
> SCIP can also be used as pure MIP solver or as<br>
> framework for branch-cut-and-price.<br>
> <br>
> You can download the complete source code of the<br>
> current version 0.80 from<br>
> <br>
> http://scip.zib.de<br>
> <br>
> SCIP is free of charge for academic institutions and<br>
> non-commercial use. If you<br>
> want to use it as a commercial institution, you have<br>
> to obtain a commercial License<br>
> from ZIB.<br>
> (Because SCIP is not free of charge for commercial<br>
> use, I could not incorporate it into<br>
> the COIN project.)<br>
> <br>
> SCIP has the following features:<br>
> * framework for branching, cutting, pricing and<br>
> propagation<br>
> * multi LP solver support through an LP interface,<br>
> currently supporting<br>
> - CPLEX<br>
> - Soplex<br>
> - CLP<br>
> * highly flexible through many possible user<br>
> extensions:<br>
> - constraint handlers to implement arbitrary<br>
> constraints, currently supporting<br>
> linear constraints and some specializations<br>
> like knapsack and set packing,<br>
> set covering, and set partitioning<br>
> - separators to apply cutting planes on the LP<br>
> relaxation<br>
> * clique cuts<br>
> * c-MIR cuts<br>
> * Gomory mixed integer cuts<br>
> * implied bound cuts<br>
> * strong CG cuts<br>
> - pricers to dynamically generated problem<br>
> variables<br>
> - domain propagators to reduce the variables'<br>
> domains<br>
> - primal heuristics<br>
> * several diving heuristics, including<br>
> guided dives<br>
> * two different rounding heuristics<br>
> * Local Branching<br>
> * RINS<br>
> * Octane<br>
> - node selectors to guide the search<br>
> - branching rules to split the problem into<br>
> subproblems<br>
> * full strong branching<br>
> * inference branching<br>
> * least/most fractional branching<br>
> * pseudo cost branching<br>
> * reliability branching<br>
> - relaxators to incorporate relaxations<br>
> additional to the LP relaxation (e.g. SDP)<br>
> - presolvers to simplify the solved problem<br>
> - file readers to understand different input<br>
> file formats<br>
> * MPS format<br>
> * LP format<br>
> * ZIMPL models (needs ZIMPL library)<br>
> - event handlers to get informed each time a<br>
> node was solved, a specific<br>
> variable changed its bounds, a new solution<br>
> was found, ...<br>
> * every existing unit is implemented as a user<br>
> extension, leading to an<br>
> interface flexible enough to meet the needs of<br>
> most additional user extensions<br>
> * cut pool management<br>
> * arbitrarily many children per node, branching on<br>
> constraints<br>
> * possibility to solve or not to solve the LP<br>
> relaxation at each single node<br>
> * conflict analysis to learn from infeasible<br>
> subproblems<br>
> <br>
> I would be glad, if you try to implement your own<br>
> cutting plane separators,<br>
> primal heuristics, branching rules, constraint<br>
> handlers, and so on with the SCIP<br>
> framework and send it to me such that I can<br>
> incorporate the code into the official<br>
> version of SCIP.<br>
> Although there is only a doxygen documentation, you<br>
> should be able (with my help)<br>
> to implement your code (in C or C++) as plugin for<br>
> SCIP.<br>
> <br>
> <br>
> Regards, Tobias Achterberg<br>
> <br>
> <br>
> -- <br>
> Tobias Achterberg Konrad-Zuse-Zentrum
fuer<br>
>
Informationstechnik<br>
> Berlin<br>
> Tel: +49 (0)30 84185-301 Takustr. 7<br>
> Email: achterberg@zib.de D-14195 Berlin, Germany<br>
> <br>
> <br>
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> End of Coin-discuss Digest, Vol 11, Issue 9<br>
> *******************************************<br>
> <br>
<br>
<br>
Carl Wilburn<br>
(901)240-5684<br>
csw_iii@yahoo.com<br>
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