nonlcon : Too many input arguments.

Hi friends, I have a problem with optimization algorithm like GA, fmincon and patternsearch. When I try to add constrain to my problem error below appear:

Error using Constrain
Too many output arguments.

Error in poptimfcnchk (line 58)
            [cineq,ceq] = feval(nonlcon,reshapeinput(Xin,X),conFcnArg{:});

Error in patternsearch (line 343)
[Iterate,OUTPUT.funccount] = poptimfcnchk(FUN,nonlcon,initialX,Iterate, ...

Error in Main (line 30)
[x,Fval,exitFlag,output]=patternsearch(@(x)
Objective(x),X0,[],[],[],[],LB,UB,@Constrain,options)

Caused by:
    Failure in initial user-supplied nonlinear constraint function evaluation.
    PATTERNSEARCH cannot continue.

However, when I omit the constrain from optimization it works very well. After adding adding constrain to my problem this error occur. Could anyone help???

Thanks.

[Torsten]

You will have to show us your function with name "Constrain".

Best wishes

Torsten.

[Ali T]

The Constrain function is not like what other simple functions. Because of sizing component which runs with ADVISOR is implemented, it may sounds weird to you. Anyway, I bring me code down there:

function Con=Constrain(x)

input.accel.param = {'spds','max_speed_bool'} ;
input.accel.value = {[0 37.28]};%;37.28 55.9234]} ;
[error, resp] = adv_no_gui('accel_test',input) ;

accel_1 = resp.accel.times(1) ;
MaxSpeed = resp.accel.max_speed*1.60934 ; 

if ~error
Con=[accel_1/10-1;1-MaxSpeed/100];
end

Answer 1

[Alan Weiss]

To quote the documentation on nonlinear constraints, "Nonlinear constraint functions must return both c and ceq, the inequality and equality constraint functions, even if they do not both exist. Return empty [] for a nonexistent constraint."

In other words, you need to rewrite your constraint function as follows, assuming your existing constraints are inequality rather than equality constraints:

function [Con,coneq] = Constrain(x)

Con = [];
coneq = [];
input.accel.param = {'spds','max_speed_bool'} ;
input.accel.value = {[0 37.28]};%;37.28 55.9234]} ;
[error, resp] = adv_no_gui('accel_test',input) ;

accel_1 = resp.accel.times(1) ;
MaxSpeed = resp.accel.max_speed*1.60934 ; 

if ~error
Con=[accel_1/10-1;1-MaxSpeed/100];
end

Alan Weiss

MATLAB mathematical toolbox documentation

[Ali T]

Marvelous, that worked... amazing, thank you. Unfortunately I am not convinced why do I have to use con=[] and coneq=[] ??? When I ran my code, something new error pops up... Could you please help me solving this error too???

Error in adv_no_gui case {accel_test}:

    Index exceeds matrix dimensions.
    Attempt to reference field of non-structure array.

    Error in Constrain (line 11)
    accel_1 = resp.accel.times(1) ;

    Error in poptimfcnchk (line 58)
                [cineq,ceq] = feval(nonlcon,reshapeinput(Xin,X),conFcnArg{:});

    Error in patternsearch (line 343)
    [Iterate,OUTPUT.funccount] = poptimfcnchk(FUN,nonlcon,initialX,Iterate, ...

    Error in Main (line 30)
    [x,Fval,exitFlag,output]=patternsearch(@Objective,X0,[],[],[],[],LB,UB,@Constrain,options)

    Caused by:
        Failure in initial user-supplied nonlinear constraint function evaluation.
        PATTERNSEARCH cannot continue.