MaxFunctionEvaluations not working in optimset() for fsolve()

I want to solve a 3x3 system numerically. Nevertheless at given initial guess values it prompts

Solver stopped prematurely.

fsolve stopped because it exceeded the function evaluation limit,
options.MaxFunctionEvaluations = 3.000000e+02.

To assess whether it's unable to solve the system for lack of enough function evaluations or iterations, I tried to set:

options.MaxIterations = 1000;
options.MaxFunctionEvaluations = 4000;

Nonetheless, no matter what value I put, I always get

options.MaxFunctionEvaluations = 3.000000e+02.

I'd appreciate if you may help me in how to increase the number of function evaluations and maximum iterations.

PD: My code looks like this:

function F = three_by_three_system(x, params)
    %some ;
end

x0 = [1 1 1];

options = optimset('Display', 'on', 'TolX', 1e-10, 'TolFun', 1e-10);
options.MaxIterations = 1000;
options.MaxFunctionEvaluations = 4000;

x1 = fsolve(@(x) three_by_three_system(x, params), x0,options);

and no matter what I put in lines 7 and 8, always get:

Solver stopped prematurely.

fsolve stopped because it exceeded the function evaluation limit,
options.MaxFunctionEvaluations = 3.000000e+02.

Thanks!!

EDIT: Seems like MaxFunctionEvaluations is not an option for optimset(), but for optimoptions(), which only works for optimization but not for solving equations to zero. Besides, it's not completely clear what to do in order to increase the function evaluations for my optimization, what should I do?

[Ram Iyer]

I have tried both optimset and optimoptions with no effect. Below is the code with optimset

options = optimset('fsolve');
options.Algorithm = 'levenberg-marquardt';
options.MaxIterations = 1000; % Solver shows this value to be 400 no matter what.
options.MaxIter = 1000; % This field is shown in the structure for 'fsolve' with value 400.
options

options = struct with fields:
                   Display: 'final'
               MaxFunEvals: []
                   MaxIter: 1000
                    TolFun: 1.0000e-06
                      TolX: 1.0000e-06
               FunValCheck: 'off'
                 OutputFcn: []
                  PlotFcns: []
           ActiveConstrTol: []
                 Algorithm: 'levenberg-marquardt'
    AlwaysHonorConstraints: []
           DerivativeCheck: 'off'
               Diagnostics: 'off'
             DiffMaxChange: Inf
             DiffMinChange: 0
            FinDiffRelStep: []
               FinDiffType: 'forward'
         GoalsExactAchieve: []
                GradConstr: []
                   GradObj: []
                   HessFcn: []
                   Hessian: []
                  HessMult: []
               HessPattern: []
                HessUpdate: []
          InitBarrierParam: []
     InitTrustRegionRadius: []
                  Jacobian: 'off'
                 JacobMult: []
              JacobPattern: 'sparse(ones(jrows,jcols))'
                LargeScale: []
                  MaxNodes: []
                MaxPCGIter: 'max(1,floor(numberofvariables/2))'
             MaxProjCGIter: []
                MaxSQPIter: []
                   MaxTime: []
             MeritFunction: []
                 MinAbsMax: []
        NoStopIfFlatInfeas: []
            ObjectiveLimit: []
      PhaseOneTotalScaling: []
            Preconditioner: []
          PrecondBandWidth: Inf
            RelLineSrchBnd: []
    RelLineSrchBndDuration: []
              ScaleProblem: 'none'
       SubproblemAlgorithm: []
                    TolCon: []
                 TolConSQP: []
                TolGradCon: []
                    TolPCG: 0.1000
                 TolProjCG: []
              TolProjCGAbs: []
                  TypicalX: 'ones(numberofvariables,1)'
               UseParallel: 0
             MaxIterations: 1000

Solver stopped prematurely.

fsolve stopped because it exceeded the iteration limit,

options.MaxIterations = 4.000000e+02.

[Torsten]

MaxIter is set to 1000 in the options structure (see above).

Did you include "options" in the call to "fsolve" :

x = fsolve(fun,x0,options)

?

Please show us the relevant part of your code so that we can reproduce the error message.

Answer 1

[Stephan]

See the documentation: