Why this piece of code gives error?

The following piece of code gives error:

Positions=rand(30,3);
fobj=@fun4sn0;
for i=1:size(Positions,1)
    Fit(i) = fobj(Positions(i,:));
end

The error it gives is as:

Array indices must be positive integers or logical values.

Error in fun4sn0 (line 18)

xo(1,k)=xo(1,k)+u(i)*exp(-1i*(k-1)*pi*cosd(u(P+i)));

Error in abc (line 4)

Fit(i) = fobj(Positions(i,:));

[KSSV]

Show us your function @fun4sn0

Answer 1

[Walter Roberson]

Positions=rand(30,3);

Three columns

 Fit(i) = fobj(Positions(i,:));

You pass in one row at a time, so you pass in a vector with one row and three columns.

function e=fun4sn0(pop)

where it is received as pop

C = size(pop,2);
P=C/2;

3 columns so C is 3 and P is 1.5

        for i=1:P

i is 1:1.5 which will be just 1

   xo(1,k)=xo(1,k)+u(i)*exp(-1i*(k-1)*pi*cos(u(P+i)));

P is 1.5 so P+i will be 2.5 and you will be indexing u at 2.5 which is not a valid index

u=[25 45 ];% desired vector

You hard-coded u to be length 2 but you can see that you are indexing u according to the size of the input vector, which will be a problem if the input gets larger.

[Sadiq Akbar]

Thanks a lot for your help.