Errors in solving nonlinear simultaneous equations

Hello all, I'm trying to solve nonlinear simultaneous equations. However, Matlab is giving errors, which I cannot rectify. Any help is much appreciated.

I made a function file:

function [ f ] = nlsimul( x)
%nlsimul has two nonlinear simultaneous equations in variable x(1), x(2)
f = [-2*(x(1).^2).*exp(-x(1).^2-(x(2).^2))+exp(-x(1).^2-(x(2).^2)); ...
    -2.*x(1).*x(2)*exp(-x(1).^2-(x(2).^2))];

end

Then I made a script file to solve this system of equations:

%This script calles nlsimul() to solve nonlinear simultaneous equations

options = optimoptions('fsolve','Diagnostics','on','Display','iter','PlotFcns','@optimplotresnorm');
x0=[2,2];
[x,fval,exitflag,output] = fsolve(@nlsimul,x0,options)

Upon running this script file, Matlab gives several errors. Can someone help?

Answer 1

[Sven]

You can't plot a simultaneous equation during iterations in that way.

If you instead put:

options = optimoptions('fsolve','Diagnostics','on','Display','iter');

Then your optimisation runs perfectly.

If you instead put (note the function handle rather than string):

options = optimoptions('fsolve','Diagnostics','on','Display','iter','PlotFcns',@optimplotresnorm);

Then it solves fine as well... it's too quick to see anything plotted though...

Did that help you out?

[Amit Kumar]

indeed helpful reply! thanks a lot!