using genetic algorithm for optimization

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mado
mado 2013-3-29
i have this error message
??? Subscripted assignment dimension mismatch.
Error in ==> fcnvectorizer at 14
y(i,:) = feval(fun,(pop(i,:)));
Error in ==> makeState at 47
Score =
fcnvectorizer(state.Population(initScoreProvided+1:end,:),FitnessFcn,1,options.SerialUserFcn);
Error in ==> gaunc at 41
state = makeState(GenomeLength,FitnessFcn,Iterate,output.problemtype,options);
Error in ==> ga at 279
[x,fval,exitFlag,output,population,scores] = gaunc(FitnessFcn,nvars, ...
Error in ==> main at 11
[x,fval,exitflag,output,final_pop]=ga(FitnessFcn,nvar,options);
Caused by:
Failure in user-supplied fitness function evaluation. GA cannot continue.

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采纳的回答

Alan Weiss
Alan Weiss 2013-3-29
Apparently there is an error in your fitness function. If it isn't too long, please post it so we can see what might be the problem.
And please include your gaoptimset calls and your function call to ga (e.g., x = ga(@main,4,A,b) )
Alan Weiss
MATLAB mathematical toolbox documentation

更多回答（3 个）

Walter Roberson
Walter Roberson 2013-3-29
Your fitness function is returning your input values x_pop as its first return value. It should not be doing that. The documentation indicates,
fitnessfcn
Handle to the fitness function. The fitness function should accept a row vector of length nvars and return a scalar value.
When the 'Vectorized' option is 'on', fitnessfcn should accept a pop-by-nvars matrix, where pop is the current population size. In this case fitnessfcn should return a vector the same length as pop containing the fitness function values. fitnessfcn should not assume any particular size for pop, since ga can pass a single member of a population even in a vectorized calculation.
So your fitnessfcn should only be returning a single variable, not two variables, and (unless you have Vectorized turned on) return a scalar such as fx_val .
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mado
mado 2013-3-29
do you mean that i should write it function [ fx_val]=PID_objfun_ITAE(x_pop,options)

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mado
mado 2013-3-29
编辑：Walter Roberson 2013-3-29
this is the fitness function code
function [x_pop, fx_val]=PID_objfun_ITAE(x_pop,options)
KP=x_pop(1);
KI=x_pop(2);
simopt = simset('solver','ode45','SrcWorkspace','Current','DstWorkspace','Current'); % Initialize sim options
[tout,xout,yout] = sim('pid_INC_GA',[0 .1],simopt);
t =0:0.1:30;
for i=1:301
error(i) = (abs(26.3-yout(i)))*t(i);
error=error*error';
ISE=sum(error);
end
sys_overshoot=max(yout)-26.3; % compute the overshoot
alpha=10;beta=1;
fx_val=ISE*beta+sys_overshoot*alpha;
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Walter Roberson
Walter Roberson 2013-3-29
Put a breakpoint at the fx_val assignment. Run the program. When it stops, show us
size(ISE)
size(sys_overshoot)
size(ISE*beta+sys_overshoot*alpha)
If those values look reasonable, use the command
dbcont
to continue. See if you again stop at the same line, or if you get an error first. If you again stop at the same line then the problem is not triggered immediately so you should test those sizes and continue executing until you see something odd.
My speculation is that at some point an empty matrix is being generated.
mado
mado 2013-3-29
size of them all are [1 1] and i typed dbcont it gives the error message directly

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mado
mado 2013-3-30
i make the function return one variable fx-val but the program is iterating as it is in a loop and restart its work without stopping i don't think its the for loop of error cause i removed it and it gives error message this is a part of it "??? Error using ==> PID_objfun_ITAE at 28 Error due to multiple causes.
Error in ==> validate>@(x)fitness(x,FitnessFcnArgs{:}) at 136 fitness = @(x) fitness(x,FitnessFcnArgs{:});

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