[Symphony] [SYMPHONY] error in lp_rowfunc.c, line 444

[Menal Guzelsoy]

Sam,

Can you make sure that the indices array of each cut is properly
allocated/filled and is compatible with the size of the cut?

Menal.

Menal Guzelsoy
1610 4620455


On Fri, Aug 13, 2010 at 11:15 AM, S R <sr.pointe at gmail.com> wrote:
> Hi.  I have developed a custom application using symphony version
> 5.2.4 with MSVC (windows) to solve a specific type of integer program.
>  As part of my application, I generate cuts in user_find_cuts and add
> them using cg_add_explicit_cut.  For some problems, I get an error
> "Unhandled exception at 0x008b80b4 in Test.exe: 0xC0000005: Access
> violation reading location 0xf0bdff60" in file lp_rowfunc.c at line
> 444.  The line is
>
>         lhs += matval[j] * x[matind[j]];
>
> If I inspect the values of each variable, they seem reasonable except
> matind[j] = -33686019.  This then causes the exception when
> x[matind[j]] is evaluated.  I have not been able to figure out much
> else.  The call stack is:
>
>        compute_violations(LP_PROB * p=0x00d8b670, int new_row_num=1,
> WAITING_ROW * * new_rows=0x00d17f28)  Line 444 + 0x15 bytes     C++
>        add_new_rows_to_waiting_rows(LP_PROB * p=0x00d8b670, WAITING_ROW * *
> new_rows=0x00d17f28, int new_row_num=1)  Line 295 + 0x11 bytes  C++
>        generate_cuts_in_lp_u(LP_PROB * p=0x00d8b670)  Line 2289 + 0x18 bytes   C++
>        receive_cuts(LP_PROB * p=0x00d8b670, int first_lp=0, int
> no_more_cuts_count=0)  Line 371 + 0x9 bytes     C++
>        fathom_branch(LP_PROB * p=0x00d8b670)  Line 445 + 0x12 bytes    C++
>        process_chain(LP_PROB * p=0x00d8b670)  Line 184 + 0x9 bytes     C++
>        solve(TM_PROB * tm=0x00dabe98)  Line 397 + 0x18 bytes   C++
>        sym_solve(SYM_ENVIRONMENT * env=0x00336010)  Line 1150 + 0xc bytes      C++
>        OsiSymSolverInterface::branchAndBound()  Line 89 + 0xc bytes    C++
>        main(int argc=5, char * * argv=0x00333b48)  Line 6102   C++
>
> I have not been able to make much progress in figuring out what is
> going on.  Looking at the output, I see that the one iteration
> completes successfully.  The error occurs after "Starting iteration 2"
> is displayed.  This seems to indicate that my general
> approach/syntax/etc. are correct.  Of course, if I remove my user
> generated cuts, I do not receive an error.  If I examine the cuts I am
> trying to add, I don't see anything incorrect about them.  But it
> seems likely that I am doing something wrong.
>
> Does anyone have any suggestions/hint/wisdom?  Any guidance on how to
> debug this?
>
> Thanks,
> Sam
>
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