[Help-glpk] primal heuristics

[Rafael Espíndola]

Using IOS,  what is the best place run a primal heuristic? Currently
we are using IOS_V_BRANCH. The problem is that sometimes GLPK will
overwrite ios->best with an inferior solution. To solve this, the
program keeps a copy of the best solution in a safe place and always
checks if ios->best was overwritten.

What do you think about adding a new callback (IOS_V_PRIMAL?) that
would be called before IOS_V_BRANCH. After calling this callback GLPK
would call cleanup_the_tree to   try to prune some branches.

Would a patch implementing this idea be welcome?

Rafael