Re: [Help-glpk] Hit an assert

[Neill Clift]

Hi,
My code calls glpk with an integer program to solve hundreds of 
thousands of times.
I tried writing out the problematic problem with glp_write_prob but it 
wouldn't read that back in. Using glp_write_lp or glp_write_mps followed 
by the read function would create a problem that could be solved.
So I got the program to write out some code to reproduce it. See the 
attached routine.
I am running this on Windows 10 x64. Compiled the library with VS 2015. 
Stack looks like this:

     glpk_4_57.dll!abort() Line 88    C
    glpk_4_57.dll!errfunc(const char * fmt, ...) Line 55    C
     glpk_4_57.dll!_glp_sgf_reduce_nuc(LUF * luf, int * k1_, int * k2_, 
int * cnt, int * list) Line 185    C
     glpk_4_57.dll!_glp_sgf_factorize(SGF * sgf, int singl) Line 1343    C
     glpk_4_57.dll!_glp_lufint_factorize(LUFINT * fi, int n, 
int(*)(void *, int, int *, double *) col, void * info) Line 146    C
     glpk_4_57.dll!_glp_fhvint_factorize(FHVINT * fi, int n, 
int(*)(void *, int, int *, double *) col, void * info) Line 52    C
     glpk_4_57.dll!_glp_bfd_factorize(BFD * bfd, int m, int(*)(void *, 
int, int *, double *) col1, void * info1) Line 218    C
     glpk_4_57.dll!_glp_spx_factorize(SPXLP * lp) Line 56    C
     glpk_4_57.dll!dual_simplex(csa * csa) Line 745    C
     glpk_4_57.dll!_glp_spy_dual(glp_prob * P, const glp_smcp * parm) 
Line 1158    C
     glpk_4_57.dll!solve_lp(glp_prob * P, const glp_smcp * parm) Line 
250    C
     glpk_4_57.dll!glp_simplex(glp_prob * P, const glp_smcp * parm) 
Line 459    C
     glpk_4_57.dll!_glp_ios_solve_node(glp_tree * tree) Line 1359 C
     glpk_4_57.dll!_glp_ios_driver(glp_tree * T) Line 1036    C
     glpk_4_57.dll!solve_mip(glp_prob * P, const glp_iocp * parm, 
glp_prob * P0, NPP * npp) Line 252    C
     glpk_4_57.dll!preprocess_and_solve_mip(glp_prob * P, const 
glp_iocp * parm) Line 411    C
     glpk_4_57.dll!glp_intopt(glp_prob * P, const glp_iocp * parm) Line 
630    C
     split.exe!error() Line 1644    C

Thanks.
Neill.

On 1/6/2016 12:06 PM, Neill Clift wrote:
> Is this likely a problem with my code or a bug in glpk? Looks to be 
> reproducible. I can dump more info if needed.
>
> Assertion failed: tcol[csa->p] != 0.0
> Error detected in file ..\src\simplex\spydual.c at line 999
>
>       /* FIXME: tcol[p] and trow[q] should be close to each other */
>       xassert(tcol[csa->p] != 0.0);
>
>      glpk_4_57.dll!abort() Line 88    C
>      glpk_4_57.dll!errfunc(const char * fmt, ...) Line 55    C
> >    glpk_4_57.dll!dual_simplex(csa * csa) Line 999    C
>      glpk_4_57.dll!_glp_spy_dual(glp_prob * P, const glp_smcp * parm) 
> Line 1158    C
>      glpk_4_57.dll!solve_lp(glp_prob * P, const glp_smcp * parm) Line 
> 250    C
>      glpk_4_57.dll!glp_simplex(glp_prob * P, const glp_smcp * parm) 
> Line 459    C
>      glpk_4_57.dll!_glp_ios_solve_node(glp_tree * tree) Line 1359 C
>      glpk_4_57.dll!_glp_ios_driver(glp_tree * T) Line 1036    C
>      glpk_4_57.dll!solve_mip(glp_prob * P, const glp_iocp * parm, 
> glp_prob * P0, NPP * npp) Line 252    C
>      glpk_4_57.dll!glp_intopt(glp_prob * P, const glp_iocp * parm) 
> Line 627    C
>      split.exe!DoSimplex(_BLIST * List, unsigned long n, unsigned long 
> index, _OPERATION operation, unsigned long min, unsigned char * 
> Feasable) Line 1086    C
>
>
>
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error.c
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