Warning when runing fsolve

When I run fsolve, there's a warning:

Warning: Trust-region-dogleg algorithm of FSOLVE cannot handle non-square systems; using Levenberg-Marquardt algorithm instead.

> In fsolve at 303

Solver stopped prematurely.

fsolve stopped because it exceeded the function evaluation limit, options.MaxFunEvals = 1000 (the default value).

How can I fixed that? Thank you!

Answer 1

[Shashank Prasanna]

The Warning is acceptable. If you are running the code I gave you, you already know it is not a SQUARE system.

As with all iterative problems, you will have to play around with Tolerances to achieve the results you want. Relax the MaxFunEvals that Walter mentioned using OPTIMSET:

http://www.mathworks.com/help/optim/ug/optimset.html

I really really advise you read this since you are new to optimization in MATLAB:

http://www.mathworks.com/help/optim/ug/when-the-solver-fails.html

[Fan]

Thank you very much for your suggestion and sorry for the late reply.

But could you tell me how can I change the algorithm to Levenberg-Marquardt algorithm if I want to see the difference between them?

[Shashank Prasanna]

options=optimset('Algorithm','Levenberg-Marquardt');

please see the documentation on optimset

[Fan]

Thank you very much!

Answer 2

[Walter Roberson]

Pass in an options structure that indicates the algorithm and MaxFunEvals that you want to use.

[Fan]

Thank you very much for your suggestion and sorry for the late reply.

But could you tell me how can I change the algorithm to Levenberg-Marquardt algorithm if I want to see the difference between them?