Dear Users,

I have designed a MINLP problem and using AOA as solver. The reason I have to use AOA is my problem has goniometric functions and therefore BARON cannot be used. Also, I am using educational license which restrict KNITRO to solve problem over a specific size. When I solve problem using AOA such that it has initial solution (from a small solved network by knitro or AOA), I get final optimal solution in few seconds by AOA. For example, I solve a 4 node network using KNITRO and use this solution to solve 5 node network by AOA and in this way I gradually increase network size and keep getting result by AOA using solution from previous smaller network. This works fine. But, if I want to solve a network with no initial solution, either I get “infeasible solution” (although it has feasible solution in real) or solution time becomes so high and non-stopping (in hours). I have tried setting a bigger value of relative MIP optimality tolerance and MultiStart and increasing the Maximum Iteration, but nothing works. Any suggestions or feedback is appreciated. Thanks and Regards.

**Best answer by Marcel Hunting**