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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=DE link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hello,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>thank you very much for your work!<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>As I’ll be away for the holidays, I’ll try your patch in the new year and will report back.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Can you elaborate on the cut generator problem? Is it user-specified which one is used, or is this a choice done by the algorithm?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>And can you point me at the source code for them, so that I can check them for thread safety in case we actually use them?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regards,<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>Cornelius Riemenschneider<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>--<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>ITscope GmbH<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>Ludwig-Erhard-Allee 20<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>76131 Karlsruhe<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>Email: cornelius.riemenschneider@itscope.de<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>https://www.itscope.com<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>Handelsregister: AG Mannheim, HRB 232782<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>Sitz der Gesellschaft: Karlsruhe<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.5pt;font-family:Consolas;color:#1F497D'>Geschäftsführer: Alexander Münkel, Benjamin Mund, Stefan Reger<o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>Von:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> john.forrest@fastercoin.com [mailto:cbc-bounces@list.coin-or.org] <b>Im Auftrag von </b>John Forrest<br><b>Gesendet:</b> Mittwoch, 18. Dezember 2013 14:23<br><b>An:</b> cbc@list.coin-or.org<br><b>Betreff:</b> Re: [Cbc] Threadsafe usage of Cbc<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Cornelius,<br><br>I have made some changes, which I hope will be enough for you. I have done the minimum amount of work.<br><br>I don't think they can hurt anyone but as Ted Ralphs is preparing a new release, I will delay updating Cbc/stable/CbcSolver.?pp for a day or two. If anyone wants to test the code I attach CbcSolver.?pp.<br><br>You need to compile with -DCBC_THREAD_SAFE. The main thing this does is that Cbc only reads argv/argc type parameters in a crude threadsafe way. You also need to use alternative versions of CbcMain0/1.<br><br>parallel.cpp has been added to Cbc/examples which is a simple example.<br><br>Please tell me if there are any problems. Some lesser used Cgl cut generators may not be threadsafe, but I think the commonly used ones are.<br><br>John Forrest<br><br><br>On 17/12/13 15:11, Cornelius Riemenschneider wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Hello,<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>we use CBC via googles or-tools from java in our application.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Compared to scientific problems, our problems are small and solved by Cbc in <1s (which is great!).<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>As we process requests from users concurrently, we’d also like to call Cbc concurrently.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Currently, this is impossible, because Cbc uses the static parameters array in CbcMain0 and CbcMain1 and thus crashes or reads incorrect parameters.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>One backtrace, for example is:<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>#2 0x00007fb3435bf52b in __libc_message (do_abort=<optimized out>, fmt=<optimized out>) at ../sysdeps/unix/sysv/linux/libc_fatal.c:189<br>#3 0x00007fb3435c8d76 in malloc_printerr (action=3, str=0x7fb3436a1248 "double free or corruption (!prev)", ptr=<optimized out>) at malloc.c:6283<br>#4 0x00007fb3435cdaac in *__GI___libc_free (mem=<optimized out>) at malloc.c:3738<br>#5 0x00007fb342733f06 in std::string::assign(std::string const&) () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6<br>#6 0x00007fb2d652cb7b in establishParams(int&, CbcOrClpParam*) () from libjnilinearsolver.so<br>#7 0x00007fb2d64edc3b in CbcMain0(CbcModel&) () from libjnilinearsolver.so<br>#8 0x00007fb2d6511bec in callCbc(char const*, CbcModel&) () from libjnilinearsolver.so<br>#9 0x00007fb2d64e3fce in operations_research::CBCInterface::Solve(operations_research::MPSolverParameters const&) () from libjnilinearsolver.so<br>#10 0x00007fb2d64cfe45 in operations_research::MPSolver::Solve(operations_research::MPSolverParameters const&) () from libjnilinearsolver.so<br>#11 0x00007fb2d64cff3b in operations_research::MPSolver::Solve() () from libjnilinearsolver.so<br>#12 0x00007fb2d64c91cf in Java_com_google_ortools_linearsolver_mainJNI_MPSolver_1solve_1_1SWIG_10 () from libjnilinearsolver.so<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'># from here on it’s just the JVM<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>As I don’t know the code and it’s hard to read, I can’t really fix the problem by myself,<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>but wouldn’t it be better to move parameters inside CbcModel instead of having a static array laying around?<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Andi f that’s done (or another solution is found), do you know of any thread-safety issues in cbc?<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Keep in mind, we don’t want Cbc to solve our problem in multiple threads, we just want to be able to solve different problems simultaneous.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Regards,<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Cornelius Riemenschneider<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>--<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>ITscope GmbH<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Ludwig-Erhard-Allee 20<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>76131 Karlsruhe<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Email: <a href="mailto:cornelius.riemenschneider@itscope.de">cornelius.riemenschneider@itscope.de</a><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><a href="https://www.itscope.com">https://www.itscope.com</a><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Handelsregister: AG Mannheim, HRB 232782<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Sitz der Gesellschaft: Karlsruhe<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Geschäftsführer: Alexander Münkel, Benjamin Mund, Stefan Reger<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><p class=MsoNormal><br><br><br><o:p></o:p></p><pre>_______________________________________________<o:p></o:p></pre><pre>Cbc mailing list<o:p></o:p></pre><pre><a href="mailto:Cbc@list.coin-or.org">Cbc@list.coin-or.org</a><o:p></o:p></pre><pre><a href="http://list.coin-or.org/mailman/listinfo/cbc">http://list.coin-or.org/mailman/listinfo/cbc</a><o:p></o:p></pre></blockquote><p class=MsoNormal><o:p> </o:p></p></div></body></html>