I don't not have access to the Global Optimization Toolbox right this moment (weekend). I'll try to look, when I can. Not everyone here will have access to that add-on.

Remember that the discipline of global optimization is very difficult in general. It is an art. I have seen that toolbox work wonderfully and outperform other products.

I believe that the default method for the toolbox is branchandbound. Try changing it to multistart (or maybe even singlestart). Each method will work better than the rest for some different class of problems. For highly nonlinear functions, the multistart often does better.

No method works best for all global optimization problems. No optimizer (that I have seen) works better than all other on all problems.

Also, in global optimization the "best" solution is hard to prove, if one cannot do it analytically and has thus resorted to numerical optimizers. There might always be another (better) local minimum just over the next ridge. So it can often be a question of, "how long can you afford to wait, until you have to accept the curent best". In consequence of this you may wish to adjust the timelimit.

Try to keep Digits to at least 14 (which trunc(evalhf(Digits)) on Windows) so that Maple can evaluate objective and constraints better (in case of numerical instability of the problem).

If speed is an issue, try to ensure that objective and constraints are "evalhf'able".

Also, try setting infolevel[GlobalOptimization]:=1 or 2 to try and get an idea of how well it's doing.

You mentioned another product (scop) producing a better fit in 2 minutes. Did you have to compile the objective and constraints, when using that package?

acer