[Help-glpk] [Fwd: Re: [Fwd: Problem with GLPK when trying to find value functions]]

[Andrew Makhorin]

-------- Forwarded Message --------
From: Sergey Kuznetsov <address@hidden>
To: Robbie Morrison <address@hidden>
Cc: GLPK help <address@hidden>
Subject: Re: [Help-glpk] [Fwd: Problem with GLPK when trying to find
value functions]
Date: Thu, 26 Jul 2012 17:20:27 +0000

Hello again Robbie,


Sorry, last time I didn't ran valgrind correctly. My binary called
'test' so it's probably ran /usr/bin/test
But now I run my binary for sure and it works!!!
I guess if I don't find bag in my code I will use valgrind.
But I still want to find the bag just for self-learning.
Again, thank you very much!


Sergey  

On Thu, Jul 26, 2012 at 5:07 PM, Sergey Kuznetsov <address@hidden>
wrote:
        Hello Robbie,
        
        
        I ran my binary under valgrind, here is summary:
        ==12805== HEAP SUMMARY:
        ==12805==     in use at exit: 0 bytes in 0 blocks
        ==12805==   total heap usage: 30 allocs, 30 frees, 1,971 bytes
        allocated
        ==12805== 
        ==12805== All heap blocks were freed -- no leaks are possible
        ==12805== 
        ==12805== ERROR SUMMARY: 0 errors from 0 contexts (suppressed:
        11 from 6)
        --12805-- 
        --12805-- used_suppression:     11 U1004-ARM-_dl_relocate_object
        ==12805== 
        ==12805== ERROR SUMMARY: 0 errors from 0 contexts (suppressed:
        11 from 6)
        
        
        and still the same problem as before running under valgrind:
        *** glibc detected *** ./test: free(): invalid pointer:
        0x0828f350 ***
        ======= Backtrace: =========
        /lib/i386-linux-gnu/i686/cmov/libc.so.6(+0x6e3f1)[0xb74773f1]
        /lib/i386-linux-gnu/i686/cmov/libc.so.6(+0x6fc58)[0xb7478c58]
        /lib/i386-linux-gnu/i686/cmov/libc.so.6(cfree+0x6d)[0xb747bd0d]
        /usr/lib/libglpk.so.0(glp_free+0x141)[0xb76ed6b1]
        ======= Memory map: ========
        ....
        
        
        >One other thought: GLPK is not officially thread safe:
        >do you call GLPK concurrently?
        At first, I ran GLPK in omp parallel for, it didn't enough
        memory for big instances, that's why I'm using in a loop:
        for each right-hand side{
           call GLPK;
           store optimal value;  
        }
        Thanks,
        
        
        Sergey
         
        
        On Thu, Jul 26, 2012 at 4:41 PM, Robbie Morrison
        <address@hidden> wrote:
                
                Hello Sergey
                
                ------------------------------------------------------------
                To:           address@hidden
                Subject:      Problem with GLPK when trying to find
                value functions
                
                From:         Sergey Kuznetsov <address@hidden>
                Date:         Wed, 25 Jul 2012 19:19:39 +0000
                
                ------------------------------------------------------------
                
                > Hello,
                >
                > I'm using GLPK to find value functions, it's a family
                > of linear programs with right-hand side as parameter.
                >
                > For instance, I'm constructing 3D integer lattice and
                > at each site (point) I need to find optimal solution
                > using site coordinates as right-hand side (in this
                case
                > it's 3D vector).
                >
                > I wrote a function that solves the linear program
                using
                > GLPK. At first it crashed on the second call. I
                > replaced glp_delete_prob() on gpl_erase_prob() and it
                > worked well for [0;3]^3 lattice (and [0;3]^2
                > lattice). The problems began [0;4]^2 (2D) lattice. I
                > have segmentation fault and it's unusual because in
                > [0;3]^3 I'm solving more programs.
                >
                > OS : Linux Debian, i686;  Compiler: GCC  4.7.1
                > Test instances: 3D: 4 columns, 3 rows; 2D: 3 columns,
                2 rows;  all the
                > entries (matrix, objective function coeff, right-hand
                side) are
                > integers.
                >
                > Clearly, the problems begin when I'm setting span of
                > the lattice to 4 (5, 6, etc.).
                >
                > If anybody has any idea how to fix this, please help
                > me.  Thanks
                >
                > Sergey Kuznetsov
                
                
                Run your program under 'valgrind':
                
                  http://en.wikipedia.org/wiki/Valgrind
                  http://valgrind.org
                
                It is dead easy to do so:
                
                  $ valgrind [valgrind-options] myprog [my-options]
                
                'valgrind' should pick up initialized variables and out
                of bounds array access.
                
                If not already on your system, 'valgrind' is available
                via debian package 'valgrind' (or my system).
                
                One other thought: GLPK is not officially thread safe:
                do you call GLPK concurrently?
                
                HTH, Robbie
                ---
                Robbie Morrison
                PhD student -- policy-oriented energy system simulation
                Technical University of Berlin (TU-Berlin), Germany
                University email (redirected) :
                address@hidden
                Webmail (preferred)           : address@hidden
                [from Webmail client]