Reginald, > I've modified the test generator so it no longer has dependencies on > local libraries. I've also expanded the precision used in the > MathProg data file to reduce truncation related errors. It's attached > along w/ a Makefile and a new driver script. > > The problem manifests itself if part of the first row is populated by > zeros. The README and other files in the tarball give the details. > > If I'm mistaken in my expectation of what the simplex solver should > produce I'd greatly appreciate a pointer to an explanation of my > error. I can think of other ways to solve my problem. > > Any suggestions of further work I can do are most welcome. Also > please let me know if I've omitted something. I've been working on > this for several weeks and it's gotten to be a bit of a blur. I've > chased a lot of dead ends trying to understand why I was getting bad > results on certain problem instances. >
I generated .dat files with your tst1 script and then run bug.mod using some of data files--glpsol successfully solved all the instances. Sorry, may be I missed something, but what is the issue? > For example, is there currently a way to obtain the determinant of the > non-basic matrix in glpsol? I found lots of instances of "determine" > with "egrep determin", but none of "determinant". > Matrix determinants are generally not used in practical computations. To estimate the error in solution of a linear system and, in particular, to decide if a given matrix is close to a singular one with the working precision you may use its condition number. AFAIK, GSL has a condition estimator for dense matrices (glpk doesn't have). > > If there is not, would an optional dependency on the Gnu Scientific > Library be acceptable? That has code to compute the determinant from > an LU decomposition that I might be able to adapt to work in GLPK to > monitor the evolution of the solution. > Could you please explain what exactly do you need to do? Andrew Makhorin _______________________________________________ Help-glpk mailing list [email protected] https://lists.gnu.org/mailman/listinfo/help-glpk
