All is correct but this code gives error?

I downloaded a file from the Mathworks file exchange and tried to run it, but it was giving error. Then I commented the function definition line and defined what was used ahead. All seems correct, but when I run it, again it gives error. The piece of code is:

clear all
clc
nvars=4;% By Me
fitnessfun=@main3;
%%if nargin<3 | isempty(options)==1
    options=hPSOoptions;
%%end

if size(options.space,1)==1
    for i=1:nvars
        s(i,:)=options.space;
    end
    options.space=s;
elseif size(options.space,1)~=nvars
    error('The rows of options.space are not equal to nvars.');
end

if size(options.maxv,1)==1
    for i=1:nvars
        v(i,1)=options.maxv;
    end
    options.maxv=v;
elseif size(options.maxv,1)~=nvars
    error('The rows of options.maxv are not equal to nvars.');
end

c1 = options.c1;
c2 = options.c2;
w = options.w;
maxv = options.maxv;
space = options.space;
popul = options.bees;
flights = options.flights;
HybridIter = options.HybridIter;
Show = options.Show;
StallFliLimit = options.StallFliLimit;
StallTimeLimit = options.StallTimeLimit;
TimeLimit = options.TimeLimit;
Goal = options.Goal;

% Define the options for the hybrid approach
options = optimset('LargeScale','off','Display','off','MaxIter',HybridIter);

% Initial population (random start)
ru=rand(popul,size(space,1));
pop=ones(popul,1)*space(:,1)'+ru.*(ones(popul,1)*(space(:,2)-space(:,1))');


% Hill climb of each solution (bee)
for i=1:popul*sign(HybridIter)
    [pop(i,:),fxi(i,1)]=fminsearch(fitnessfun,pop(i,:),options,varargin{:});
end
pop=min(pop,ones(popul,1)*space(:,2)');
pop=max(pop,ones(popul,1)*space(:,1)');
fxi=feval(fitnessfun,pop,varargin{:});

Thre required functions are as below:

function e=main3(b)

u=[-30 0 40 60].';% Desired vector
M=5; %1st constant
N=10; %2nd constant
K=3; 3rd constant
d = 0.5; % 5th constant
vec = @(MAT) MAT(:); 
vecH = @(MAT) MAT(:).'; 

steerVecT = @(ang) exp(1j*2*pi*d*(0:M-1).'*sin(vecH(ang))); % Tx steer matrix of size 10 x 3 
steerVecR = @(ang) exp(1j*2*pi*d*(0:N-1).'*sin(vecH(ang))); 
%%%%%%%%%%%%%%%%%%%%
% Swapping vector b
%%%%%%%%%%%%%%%%%%%%
[~, ix] = sort(u); % u is my desired vector
[~, ix1(ix)] = sort(b);  
b = b(ix1);
A = ones(K, 1);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Calculation of yo i.e., observed response
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

steerMo = steerMatTR(deg2rad(u), steerVecT, steerVecR);
ro = steerMo*A; 
yo = ro;    

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Calculation of ye i.e., estimated y  
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

steerMe = steerMatTR(deg2rad(b), steerVecT, steerVecR); 
re = steerMe*A; 
ye = re;     
%%%%%%%%%%%%
% MSE 
%%%%%%%%%%%%
abc=0.0;
for m1=1:M*N
  abc=abc+(abs(yo(m1,1)-ye(m1,1))).^2;  
end 
abc=abc/(M*N); 
e=abc;

end %%%%%%%%%%% END of our main3s function %%%%%%%%%%%%%%%%%


%%%%%%%%%%%%%%%%%%%%%
% function called inside main3
%%%%%%%%%%%%%%%%%%%%%
function steerM = steerMatTR(targetAngle, steerVecT, steerVecR)

steerA = steerVecT(targetAngle); 
steerB = steerVecR(targetAngle);
steerM = zeros(size(steerA, 1)*size(steerB, 1), length(targetAngle));
for idxK = 1 : 1 : length(targetAngle) 
    steerM(:, idxK) = kron(steerB(:, idxK), steerA(:, idxK));
end
end

After running the above peice of code, it gives the following erro though all seems ok:

Brace indexing into the result of a function call is not supported. Assign the result of

'varargin' to a variable first, then brace index into it.

Error in hPSO1 (line 94)

fxi=feval(fitnessfun,pop,varargin{:});

[Jan]

Which FileExchange submission do you mean?

The error occurs inside hPSO1, but this is not part of the posted code and not called also. Please post a copy of the complete error message, not just a part of it.

" All seems correct, but when I run it, again it gives error." :-)

[Sadiq Akbar]

Thank you very much dear Jan for your kind response. As I have told in my posted question that the original code was giving an error. So I commented the function definition line i.e.,

" function [x,fval,gfx,output]=hPSO(fitnessfun,nvars,options,varargin)"

and defined the following which were requoired in the forthcoming code:

clear all

clc

nvars=4;% By Me

fitnessfun=@main3;

And then I switched on the debugger and ran it line by line but it gave the following error:

Brace indexing into the result of a function call is not supported. Assign the result of

'varargin' to a variable first, then brace index into it.

Error in hPSO1 (line 94)

fxi=feval(fitnessfun,pop,varargin{:});

Note1: Actually I copied the whole code of hPSO and pasted it in a new editor window and namded it as hPSO1 so that I don't loose the original code of hPSO that's why you see the name hPSO1.

Note2: I took the code from this site:

URL: https://www.mathworks.com/matlabcentral/fileexchange/6497-hybrid-particle-swarm-optimization

Answer 1

[Jan]

I guess boldly, that the code fails here:

[pop(i,:),fxi(i,1)]=fminsearch(fitnessfun,pop(i,:),options,varargin{:});
...
fxi=feval(fitnessfun,pop,varargin{:});

The posted code seems to be a script. Or did you crop the initial line

function hPSO1

? If so, this was confusing.

The initial clear all will delete all existing variables. On top of a function, this is a crude waste of time. Unfortunately it deletes all loaded functions from the memory also and the reloading is time-consuming also without having any benefits.

What is the meaning of "vargargin{:}" in the two shown lines of code? Is there a variable number of inputs to the shown piece of code (which cannot be a script then)?

By the way, youn simplify

abc=0.0;
for m1=1:M*N
  abc=abc+(abs(yo(m1,1)-ye(m1,1))).^2;  
end 
abc=abc/(M*N); 
e=abc;

to

e = mean((yo - ye).^2);

[Sadiq Akbar]

Thank you very much dear Jan for your kind response. As I have told in my posted question that the original code was giving an error. So I commented the function definition line i.e.,

" function [x,fval,gfx,output]=hPSO(fitnessfun,nvars,options,varargin)"

and defined the following which were requoired in the forthcoming code:

clear all

clc

nvars=4;% By Me

fitnessfun=@main3;

And then I switched on the debugger and ran it line by line but it gave the following error:

Brace indexing into the result of a function call is not supported. Assign the result of

'varargin' to a variable first, then brace index into it.

Error in hPSO1 (line 94)

fxi=feval(fitnessfun,pop,varargin{:});

Note1: Actually I copied the whole code of hPSO and pasted it in a new editor window and namded it as hPSO1 so that I don't loose the original code of hPSO that's why you see the name hPSO1.

Note2: I took the code from this site:

URL: https://www.mathworks.com/matlabcentral/fileexchange/6497-hybrid-particle-swarm-optimization

[Jan]

clear all deletes all variables and removes loaded functions from the memory. Inside a function all input arguments are cleared and this cannot be useful. Reloading the functions from the slow disk is a waste of time also. So omit the clear all command, because it is not useful. Maybe this solves your problems already.

[Sadiq Akbar]

Thanks a lot for your kind response dear Jan. I commented the "clear all" command and ran it again, but still it gives the following error:

Brace indexing into the result of a function call is not supported. Assign the result of

'varargin' to a variable first, then brace index into it.

Error in hPSO1 (line 94)

fxi=feval(fitnessfun,pop,varargin{:});

[Walter Roberson]

You converted a function into a script, and parts of the function broke because of that.

You should not have converted the function into a script: you should have left it a function and created a script that invokes the function with appropriate parameters.

[Sadiq Akbar]

Thank you dear Walter Roberson for your kind response. I did what you instructed me to do i.e., I converted that back to function and wrote my own script as below:

function [x,fval,gfx,output]=main()
[x,fval,gfx,output]=hPSO(@main3,4,hPSOoptions,varargin)
end

And ran it but still it's giving an error as below:

Execution of script varargin as a function is not supported:

C:\Program Files\MATLAB\R2022b\toolbox\matlab\lang\varargin.m

Error in main (line 3)

[x,fval,gfx,output]=hPSO(@main3,4,hPSOoptions,varargin)

[Walter Roberson]

function [x,fval,gfx,output] = main(varargin)
  [x,fval,gfx,output] = hPSO(@main3, 4, hPSOoptions, varargin{:})
end

[Sadiq Akbar]

Thank you very much dear Walter Roberson for your help. I did so and ran it. But it gave me the following error:

File: hPSO.m Line: 3 Column: 41

Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters,

or other syntax error. To construct matrices, use brackets instead of parentheses.

Error in main (line 3)

[x,fval,gfx,output] = hPSO(@main3, 4, hPSOoptions, varargin{:})