[SCIP] LP numerical troubles.

[James Cussens]

​Hi all,

In a SCIP project I am working on I am continually running into "unresolved numerical troubles in LP". Some example output given below. I get this whether using SOPLEX or CPLEX and whether or not I link with IPOT. I suspect that I am somehow generating "weird" LPs so I would like to inspect the LPs that are causing these problems. What's the best way to do this? (Btw, I am using both pricing and cutting in the price-and-cut loop.)

I'm using SCIP 8.0.2

James


time | node  | left  |LP iter|LP it/n|mem/heur|mdpt |frac |vars |cons |cuts |sepa|confs|strbr|  dualbound   | primalbound  |  gap   | compl.
p 3.7s|     1 |     0 |    14 |     - |shiftand|   0 |   - |9815 | 853 |   0 |  0 |   6 |   0 |      --      |-5.916805e+03 |    Inf | unknown
(node 1) unresolved numerical troubles in LP 5 -- using pseudo solution instead (loop 1)
k 3.8s|     1 |     0 |    16 |     - |roundand|   0 |   - |9815 | 853 |   0 |  0 |   6 |   0 |      --      |-2.814319e+03 |    Inf | unknown
  3.9s|     1 |     2 |    16 |     - |    91M |   0 |   - |9815 | 853 |   0 |  0 |   6 |   0 |      --      |-2.814319e+03 |    Inf | unknown
  3.9s|     2 |     3 |    18 |  16.0 |    91M |   1 |   - |9815 | 853 |   0 |  0 |   6 |   0 |      --      |-2.814319e+03 |    Inf | unknown
  4.0s|     3 |     4 |    22 |  10.0 |    91M |   2 |   - |9815 | 853 |   0 |  0 |   6 |   0 |      --      |-2.814319e+03 |    Inf | unknown
  4.0s|     4 |     5 |    24 |   7.3 |    91M |   3 |   - |9815 | 853 |   0 |  0 |   6 |   0 |      --      |-2.814319e+03 |    Inf | unknown
  4.0s|     5 |     6 |    26 |   6.0 |    91M |   4 |   - |9815 | 853 |   0 |  0 |   6 |   0 |      --      |-2.814319e+03 |    Inf | unknown
  4.0s|     6 |     7 |    28 |   5.2 |    91M |   5 |   - |9815 | 853 |   0 |  0 |   6 |   0 |      --      |-2.814319e+03 |    Inf | unknown
[solve.c:4624] ERROR: (node 7) unresolved numerical troubles in LP 10 -- aborting
[solve.c:4984] ERROR: Error <-6> in function call
[scip_solve.c:2771] ERROR: Error <-6> in function call
[scipshell.c:101] ERROR: Error <-6> in function call
[scipshell.c:468] ERROR: Error <-6> in function call
[cmain.c:104] ERROR: Error <-6> in function call
SCIP Error (-6): error in LP solver


James Cussens
Room MVB 3.26
Dept of Computer Science, University of Bristol
Phone: +44 (0)117 455 8723
https://jcussens.github.io/
Funded PhDs available in Bristol in the following areas: Data Science<http://www.bristol.ac.uk/cdt/compass/>, Interactive AI<http://www.bristol.ac.uk/cdt/interactive-ai/>, Cyber Security<http://www.bristol.ac.uk/cdt/cyber-security/> or Digital Health<http://www.bristol.ac.uk/cdt/digital-health/>.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listserv.zib.de/pipermail/scip/attachments/20221028/b8eca495/attachment.html>