Re: [Bug-glpk] spydual crash in GLPK 4.57

[Heinrich Schuchardt]

Hello Sascha,

please, provide a complete example that allows to reproduce the issue.

Best regards

Heinrich Schuchardt

http://www.xypron.de

Am 25.01.16 um 17:55 schrieb Sascha Brügmann

> Hello everyone,
> I solve many problems with GLPK and every 5000-nth problem or so (no 
> fixed number, just a hint how often it occures) GLPK terminates in the 
> middle of integer-solving my problem. The following message is then printed:
> Assertion failed: tcol[csa->p] != 0.0
> Error detected in file ..\src\simplex\spydual.c at line 999
> 
> I invoke GLPK from a Java application using glpk-java. glpk-java is able 
> to catch some occurances of this error and throw them as 
> org.gnu.glpk.GlpkException such that my programm can catch them and just 
> restart GLPK (works fine!). Unfortunately most of the occurances of the 
> error kill GLPK and the JVM instantly and there is nothing I can do. I 
> have to notice the crash manually and restart my application manually.
> 
> All my problems are only slight variations of each other. Until now I 
> couln't blame specific variations of my problem to cause this error 
> because when I let GLPK re-solve the same problem it finds a feasible 
> solution (all my problems have a feasible solution).
> 
> Parameters I invoke GLPK with:
>          glp_prob lp_native = GLPK.glp_create_prob();
>          //add constraints...
> 
>          final glp_iocp iocp = new glp_iocp();
>          GLPK.glp_init_iocp(iocp);
>          iocp.setPresolve(GLPKConstants.GLP_ON);
>          iocp.setBr_tech(GLPKConstants.GLP_BR_PCH);
>          iocp.setBt_tech(GLPKConstants.GLP_BT_BPH);
>          iocp.setMsg_lev(GLPKConstants.GLP_MSG_ON);
>          iocp.setPp_tech(GLPKConstants.GLP_PP_ALL);
>          iocp.setBinarize(GLPKConstants.GLP_ON);
>          iocp.setTm_lim(123456);
> 
>          GLPK.glp_intopt(lp_native, iocp);
> 
> Regards Sascha
> 
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