How to understand solutions provided by fsolve

Hi,

I am using fsolve to solve a system of non-linear equations. However, my solutions (from complex values to positive) and exitflag (from -2 to 1) change a lot with a change in initial values and parameter values- does that mean that I need to check my equations and there is a problem with that?

Thanks in Advance,

Arpita

Answer 1

[Star Strider]

Nonlinear optimisation functions are sensitive — and can be very sensitive — to the initial estimates. If your equations re coded correctly, there is no problem with different solutions with respect to different initial parameter estimates.

[Arpita Nehra]

Thanks, thats what I was assuming but could you provide me a very broef explanation how does fsolve thonk about the solution- just to be very clear about it or suggest me where I can read about it?

Arpita

[Star Strider]

As always, my pleasure.

The fsolve function is a root-finder. To understand how it works, see the Algorithms section of its documentation, as well as the links in the See Also section, that will link you to discussions of the various aspects of the algorithms. They explain it much better than I can.