Error in Genetic Algorithm ??

I want to solve linear system of equations Ax=b, with ... A is 27*27 matrix, b is 27*1 vector, and x is 27*1..

A_struuct=load('A.mat');
A=A_struuct.A;
obs_struct=load('obs.mat');
obsb=obs_struct.obs;
x0=ones(27,1);
Fun=@(x) norm(A*x-obs,2);
nvars=27;
best_x=ga(Fun,nvars);

Error is

Error using  * 
Inner matrix dimensions must agree.

Error in @(x)norm(A*x-obs,2)

Error in createAnonymousFcn>@(x)fcn(x,FcnArgs{:}) (line 11)
fcn_handle = @(x) fcn(x,FcnArgs{:});

Error in makeState (line 48)
            firstMemberScore = FitnessFcn(state.Population(initScoreProvided+1,:));

Error in gaunc (line 41)
state = makeState(GenomeLength,FitnessFcn,Iterate,output.problemtype,options);

Error in ga (line 348)
            [x,fval,exitFlag,output,population,scores] = gaunc(FitnessFcn,nvars, ...

Error in last_kubik (line 182)
best_x=ga(Fun,nvars);

Caused by:
    Failure in initial user-supplied fitness function evaluation. GA cannot continue.

[Jan]

I've formatted your code using the "{} Code" button. It is easy and makes your message readable.

What is "obs"? You have defined "obsb" only.

[M.Shaarawy]

sorry its obs not obsb

what do you mean with "{}Code" button

Answer 1

[Jan]

As soon as you create a standard function instead of an anonymous one, you can use the debugger to find out the details:

function y = Fun(x, obs)
y = norm(A * x - obs, 2);
end

And to call the optimization tool (anonymous function only to provide the parameter obs):

F      = @(x) Fun(x, obs);  % Or "obsb"?
best_x = ga(F, nvars);

Now enable the debugger:

dbstop if error

If Matlab stops at the error, check the dimensions of A, x and abs

[M.Shaarawy]

The result is ...

Error using @(x)norm(A*x-obs,2) Too many input arguments.

Error in @(x)Fun(x,obs)

Error in createAnonymousFcn>@(x)fcn(x,FcnArgs{:}) (line 11) fcn_handle = @(x) fcn(x,FcnArgs{:});

Error in makeState (line 48) firstMemberScore = FitnessFcn(state.Population(initScoreProvided+1,:));

Error in gaunc (line 41) state = makeState(GenomeLength,FitnessFcn,Iterate,output.problemtype,options);

Error in ga (line 348) [x,fval,exitFlag,output,population,scores] = gaunc(FitnessFcn,nvars, ...

Error in ga_new (line 2) best_x = ga(F, nvars);

Caused by: Failure in initial user-supplied fitness function evaluation. GA cannot continue.

[M.Shaarawy]

This it is error going to makeState.m

[M.Shaarawy]

I want to find x which is 27*1 vector , and now I must define its size..??