Re: Solver performance solving examples/life_goe.mod

[Domingo Alvarez Duarte]

Hello Chris !

Thank you for reply !

Can you describe in a few lines what your improvements achieved ?

I've been looking at your changes and found that you've bitten by "src/env/avl.c" avl_tree do not reject duplicate keys but do not provide a way to recover duplicates, I fixed this here https://github.com/mingodad/GLPK/commit/502da3ae23ffb4c1731cc437fd6b420ac82443d5 and I found it while trying to update your code to work with splay_tree.

See this thread https://lists.gnu.org/archive/html/bug-glpk/2020-08/msg00018.html .

Comparing your glpsol with mine solving hashi.mod we get this:

=====

# your repository compiled with  -O3 -DNDEBUG -march=native -ffp-contract=off

...

INTEGER OPTIMAL SOLUTION FOUND
Time used:   91.6 secs
Memory used: 19.6 Mb (20560460 bytes)

...

Model has been successfully processed
91.72user 0.64system 1:32.37elapsed 100%CPU (0avgtext+0avgdata 23032maxresident)k
0inputs+0outputs (0major+764597minor)pagefaults 0swaps

    =====

# your repository compiled with  -O2 -MT -MD -MP -MF

...

INTEGER OPTIMAL SOLUTION FOUND
Time used:   120.9 secs
Memory used: 19.6 Mb (20560460 bytes)

...

    Model has been successfully processed
    120.93user 1.23system 2:02.16elapsed 99%CPU (0avgtext+0avgdata
    22900maxresident)k
    0inputs+0outputs (0major+764575minor)pagefaults 0swaps

=====

#my repository compiled with -g -O3 -DNDEBUG -march=native -ffp-contract=off -DWITH_SPLAYTREE

INTEGER OPTIMAL SOLUTION FOUND
Time used:   59.2 secs
Memory used: 10.6 Mb (11130654 bytes)
...

Model has been successfully processed
58.99user 0.60system 0:59.59elapsed 99%CPU (0avgtext+0avgdata 13664maxresident)k
0inputs+0outputs (0major+397605minor)pagefaults 0swaps

=====

# ubuntu 18.04 glpsol package

INTEGER OPTIMAL SOLUTION FOUND
Time used:   70.5 secs
Memory used: 19.8 Mb (20725782 bytes)
...

Model has been successfully processed
71.49user 0.22system 1:11.71elapsed 99%CPU (0avgtext+0avgdata 23500maxresident)k
0inputs+0outputs (0major+135565minor)pagefaults 0swaps

=====

Cheers !

On 26/9/20 16:20, Chris Matrakidis wrote:

I made some performance improving patches a few years ago. You can find them in: https://github.com/cmatraki/GLPK

Best Regards,

Chris Matrakidis

On Sat, 26 Sep 2020 at 14:54, Domingo Alvarez Duarte <mingodad@gmail.com> wrote:

Hello !

Testing GLPK I left it solving examples/lie_goe.mod for more than 2
hours and it didn't found a solution (wasm and native) then I stopped
then and tried with cplex/gurobi/xpress/scip all of then gives a
solution instantly (except scip that takes 3s).

The difference is so big, have someone managed through command line
options or other means managed to get a solution quickly with glpsol ?

Any idea of how to improve GLPK to not be so behind ?

Cheers !