Re: [Help-glpk] GLPK re-endrant

[Rios, Joseph L. (ARC-AFO)]

I fell like there are a couple of conversations going on in this thread, but
then again, I'm also easily confused.

Anyway, if the goal is multi-threading, I only had to disembowel a couple of
functions to get the desired results.  I've attached a patch that shows what
I've done.  Andrew may want to avert his eyes... it isn't pretty, but it
works.  Basically you replace GLPK's memory management with regular malloc()
and free() calls within glplib07.c and then you make a couple of hacks in
glplib10.c.  I left all of the original lines as comments to better see the
changes.  If anyone tries this, please verify that the patch works as
advertised as I may have forgotten some other change I made.  Oh, my changes
were based on 4.28 I think.

My application is a column generation method where there are several
subproblems running in parallel communicating with a master problem.  It
works.  I'm running it on Linux, so I can't speak to any other platform.

As a side note, to hunt down these issues, I used Valgrind (for memory
problems) and Helgrind (for threading issues) (http://valgrind.org/).  Very
nice open source tools.   Also, these conversations from a couple years ago
are helpful:

http://lists.gnu.org/archive/html/help-glpk/2006-12/msg00018.html
http://lists.gnu.org/archive/html/help-glpk/2007-08/msg00040.html

Joey

multi_thread.patch
Description: multi_thread.patch