Re: [Bug-glpk] Crash running the RELAX-IV algorithm

[Andrew Makhorin]

> > I tried to run the new min cost flow algorithm (RELAX-IV) on a problem
> > I have using glpk-java, and the java VM crashes (it doesn't catch the
> > error) while the algorithm is processing.
> > 
> > Using a regular C program, it also crashes:
> > *** glibc detected *** ./run-relax4: free(): invalid next size
> > (normal): 0x0000000001cfb220 ***
> > 
> > It seems to be a memory issue but I am not a C specialist.

I'm very sorry. The bug is in the original RELAX-IV code. Probably I
need to contact Prof. Bertsekas, the author of RELAX-IV, to ask him for
help.

I have made some brute changes in the routine relax4, which is called
from glp_relax4, and now the latter seems to work correctly. However,
the code is very intricate, and I am absolutely not sure that my changes
does not affect the program logic, so this is only a temporary solution.

If you would like to try the changed version, please replace file
glprlx.c in glpk source directory by the attached one and rebuild the
package as usual. Please report if a similar bug will appear. Thanks.


Andrew Makhorin

glprlx.c.tar.gz
Description: application/compressed-tar