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 Author Comment/Response John Yang 08/21/10 11:24pm I have a rather formidable real valued function of several complex variables and I am trying to determine if it ever achieves negative values under certain constraints. I am trying to do this using NMinimize but the fact that complex values are involved is giving me a lot of trouble. The problem can be simplified to the following (im:=I=Sqrt[-1]): funct[p_]:=1 + Re[p*(1 + im)] NMinimize[{funct[p], 0 <= Abs[p] <= 1}, p] When I evaluate this, mathematica gives me several errors, the gist of which is the following: Invalid comparison with 1.26614+0.im attempted. And the answer it ends up giving is clearly wrong: {1., {p -> 3.36619*10^-8}} However, when I try: NMinimize[{funct[p], -1 <= p <= 1}, p] It gives me the right answer: {8.07509*10^-9, {p -> -1.}} I also tried: Assuming[Element[p1, Reals] && Element[p2, Reals], NMinimize[{funct[p1 + p2*I], 0 <= Norm[p1 + p2*I] <= 1}, {p1, p2}]] but this has the same problem as last time. Is there a way to get NMinimize to work with complex variables? Thanks, John URL: ,

 Subject (listing for 'NMinimize with Complex Variables') Author Date Posted NMinimize with Complex Variables John Yang 08/21/10 11:24pm Code for NMinimize with Complex Variables John Yang 08/26/10 6:08pm
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