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Hi Marc,</div>
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Thanks. That got me what I wanted (after adding the line #include "scip/scip_lp.h" to solve.c). Turns out the troublesome LP is infeasible, which gives me something to go on to work out what is going wrong here.</div>
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James<br>
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James Cussens</div>
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Room MVB 3.26<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Scip <scip-bounces@zib.de> on behalf of Marc Pfetsch <pfetsch@mathematik.tu-darmstadt.de><br>
<b>Sent:</b> 28 October 2022 16:00<br>
<b>To:</b> scip@zib.de <scip@zib.de><br>
<b>Subject:</b> Re: [SCIP] LP numerical troubles.</font>
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<br>
Hi James,<br>
<br>
you could add<br>
<br>
SCIP_CALL( SCIPwriteLP(set->scip, "debug.lp") );<br>
<br>
at solve.c:4624. This will write out the current LP.<br>
<br>
Also a good idea is to turn on the parameter "display/lpinfo". This will <br>
show the output of the LP-solver.<br>
<br>
Best<br>
<br>
Marc<br>
<br>
<br>
<br>
<br>
On 28/10/2022 13:55, James Cussens wrote:<br>
> Hi all,<br>
> <br>
> In a SCIP project I am working on I am continually running into <br>
> "unresolved numerical troubles in LP". Some example output given below. <br>
> I get this whether using SOPLEX or CPLEX and whether or not I link with <br>
> IPOT. I suspect that I am somehow generating "weird" LPs so I would like <br>
> to inspect the LPs that are causing these problems. What's the best way <br>
> to do this? (Btw, I am using both pricing and cutting in the <br>
> price-and-cut loop.)<br>
> <br>
> I'm using SCIP 8.0.2<br>
> <br>
> James<br>
> <br>
> <br>
> time | node | left |LP iter|LP it/n|mem/heur|mdpt |frac |vars |cons <br>
> |cuts |sepa|confs|strbr| dualbound | primalbound | gap | compl.<br>
> p 3.7s| 1 | 0 | 14 | - |shiftand| 0 | - |9815 | 853 | <br>
> 0 | 0 | 6 | 0 | -- |-5.916805e+03 | Inf | unknown<br>
> (node 1) unresolved numerical troubles in LP 5 -- using pseudo solution <br>
> instead (loop 1)<br>
> k 3.8s| 1 | 0 | 16 | - |roundand| 0 | - |9815 | 853 | <br>
> 0 | 0 | 6 | 0 | -- |-2.814319e+03 | Inf | unknown<br>
> 3.9s| 1 | 2 | 16 | - | 91M | 0 | - |9815 | 853 <br>
> | 0 | 0 | 6 | 0 | -- |-2.814319e+03 | Inf | unknown<br>
> 3.9s| 2 | 3 | 18 | 16.0 | 91M | 1 | - |9815 | 853 <br>
> | 0 | 0 | 6 | 0 | -- |-2.814319e+03 | Inf | unknown<br>
> 4.0s| 3 | 4 | 22 | 10.0 | 91M | 2 | - |9815 | 853 <br>
> | 0 | 0 | 6 | 0 | -- |-2.814319e+03 | Inf | unknown<br>
> 4.0s| 4 | 5 | 24 | 7.3 | 91M | 3 | - |9815 | 853 <br>
> | 0 | 0 | 6 | 0 | -- |-2.814319e+03 | Inf | unknown<br>
> 4.0s| 5 | 6 | 26 | 6.0 | 91M | 4 | - |9815 | 853 <br>
> | 0 | 0 | 6 | 0 | -- |-2.814319e+03 | Inf | unknown<br>
> 4.0s| 6 | 7 | 28 | 5.2 | 91M | 5 | - |9815 | 853 <br>
> | 0 | 0 | 6 | 0 | -- |-2.814319e+03 | Inf | unknown<br>
> [solve.c:4624] ERROR: (node 7) unresolved numerical troubles in LP 10 -- <br>
> aborting<br>
> [solve.c:4984] ERROR: Error <-6> in function call<br>
> [scip_solve.c:2771] ERROR: Error <-6> in function call<br>
> [scipshell.c:101] ERROR: Error <-6> in function call<br>
> [scipshell.c:468] ERROR: Error <-6> in function call<br>
> [cmain.c:104] ERROR: Error <-6> in function call<br>
> SCIP Error (-6): error in LP solver<br>
> <br>
> <br>
> James Cussens<br>
> Room MVB 3.26<br>
> Dept of Computer Science, University of Bristol<br>
> Phone: +44 (0)117 455 8723<br>
> <a href="https://jcussens.github.io/">https://jcussens.github.io/</a> <<a href="https://jcussens.github.io/">https://jcussens.github.io/</a>><br>
> Funded PhDs available in Bristol in the following areas: Data Science <br>
> <<a href="http://www.bristol.ac.uk/cdt/compass/">http://www.bristol.ac.uk/cdt/compass/</a>>, Interactive AI
<br>
> <<a href="http://www.bristol.ac.uk/cdt/interactive-ai/">http://www.bristol.ac.uk/cdt/interactive-ai/</a>>, Cyber Security
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> <<a href="http://www.bristol.ac.uk/cdt/cyber-security/">http://www.bristol.ac.uk/cdt/cyber-security/</a>> or Digital Health
<br>
> <<a href="http://www.bristol.ac.uk/cdt/digital-health/">http://www.bristol.ac.uk/cdt/digital-health/</a>>.<br>
> <br>
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