<div dir="ltr">Hi Ted, Stefan, others,<div><br></div><div>First of all, thank you very much for taking the time to reply! I'll move ahead for now using the current OsiCbcSolverInterface. As I need additional MILP-specific support/require better performance, I'll revisit the potential upgrade. I'll hit the list again at that point to talk about an upgrade strategy. </div>
<div><br></div><div>Thanks again!</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Feb 19, 2014 at 9:31 AM, Ted Ralphs <span dir="ltr"><<a href="mailto:ted@lehigh.edu" target="_blank">ted@lehigh.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">To echo what Stefan said, there is not really general agreement about the usefulness/appropriateness of OsiCbc and/or the usefulness of Osi for controlling MILP solvers in general. I personally find Osi is perfectly suitable and useful for calling MIP solvers and allows the ability to easily switch out different solvers, which is exactly what Osi is supposed to do. Yes, it is true that the design of Osi is geared towards LP solvers and the user has to understand that some of the functionality will not work when solving a MILP. Nevertheless, Osi is perfectly serviceable as an interface to MILP solvers until there is a better alternative (which will hopefully happen at some point). <br>
<br>With that said, OsiCbc is only "deprecated" inasmuch as it is not well-maintained. However, I am personally using it for cases when I really do need to access solvers through Osi. It works (subject to the aforementioned performance penalties). I would be very happy to see it worked on and its performance improved. I would also be happy to help maintain it going forward. <br>
<br>Cheers,<br><br>Ted <br></div><div class="gmail_extra"><div><div class="h5"><br><br><div class="gmail_quote">On Tue, Feb 18, 2014 at 11:16 PM, Stefan Vigerske <span dir="ltr"><<a href="mailto:stefan@math.hu-berlin.de" target="_blank">stefan@math.hu-berlin.de</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<div><br>
<br>
On 02/18/2014 05:56 PM, Matthew Gidden wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi all,<br>
<br>
I was curious about the status of an OsiSolverInterface for Cbc models. I<br>
note that the current OsiCbcSolverInterface is deprecated, and it's<br>
suggested that I use the CbcSolver interface, hence my conundrum: I'd like<br>
to use the virtual Osi interface, but I'm wary of using something that's<br>
deprecated. I was hoping the list could help me understand:<br>
a) why the Osi Cbc interface was deprecated in the first place<br>
</blockquote>
<br></div>
Noone has been developing or updating it anymore. And the performance you get with it is inferior to what you get with the usual CbcSolver interface.<br>
Also MIP support in Osi is very limited, so interest for reviving OsiCbc by the Cbc developer has been very low, I believe.<div><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
b) a suggested path forward (I assume writing my own custom interface for<br>
the CbcSolver)<br>
</blockquote>
<br></div>
driver3.cpp and driver4.cpp in Cbc/examples may be a starting point.<div><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
If the answer is writing a new Osi-to-(new)CbcSolver interface, I'd be<br>
happy to contribute that back into coin.<br>
</blockquote>
<br></div>
I know some people who would like this to see.<br>
<br>
Stefan<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Warm regards,<br>
<br>
<br>
<br>
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</blockquote></div><br><br clear="all"><br></div></div><span class="HOEnZb"><font color="#888888">-- <br>Dr. Ted Ralphs<br>Associate Professor, Lehigh University<br><a href="tel:%28610%29%20628-1280" value="+16106281280" target="_blank">(610) 628-1280</a><br>
ted 'at' lehigh 'dot' edu<br><a href="http://coral.ie.lehigh.edu/~ted" target="_blank">coral.ie.lehigh.edu/~ted</a><br>
</font></span></div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br><div dir="ltr">Matthew Gidden<br>Ph.D. Candidate, Nuclear Engineering<div>The University of Wisconsin -- Madison<br>Ph. 225.892.3192<br></div></div>
</div>