Subscripted assignment dimension mismatch

Question

here is the code listing and i got the above mentiond error at line nests(r,c)=nests(r,c)+stepsize.*randn(size(nests(r,c))); please let me now what is wrong with my code as i m new to matlab

    for r = 1:numb_of_nest % for each particle

      for c = 1:4
         u=randn(size(nests(r,c)))*sigma;
         v=randn(size(nests(r,c)));
         step=u./abs(v).^(1/beta);
         nests(r,c)=nests(r,c)+stepsize.*randn(size(nests(r,c)));

        % Apply simple bounds/limits
        ns_tmp=nests(r,c);
        I=ns_tmp<Lb(c);
        ns_tmp(I)=Lb(I);

        % Apply the upper bounds 
        J=ns_tmp>Ub(c);
        ns_tmp(J)=Ub(J);
        % Update this new move 
        nests(r,c)=ns_tmp;

         end
     end

If you're looping through both dimensions, you don't need the sizes, you're only ever handling scalars. You can also omit the . in pretty much all of those operators since you're not even dealing with matrices. — scenia

sundar - Remember Monica sundar - Remember Monica · Accepted Answer · 2014-03-18T07:21:22

     step=u./abs(v).^(1/beta);
     nests(r,c)=nests(r,c)+stepsize.*randn(size(nests(r,c)));

Here you're assigning a value to the variable step, but then using a different variable called stepsize that hasn't been assigned a value anywhere in this code. Is this intentional? If not, stepsize is probably some leftover variable from previous code which is messing up the dimensions and giving you this error.

In addition to the above, is nests an ordinary two-dimensional matrix in your code? If so, taking size(nests(r,c)) every time is unnecessary - since you're giving two subscripts, the result is only going to be 1 all the time. Or is nests a cell array perhaps? In that case, you might want to index using curly braces { } instead of ordinary parantheses, to get the size of the matrix that's sitting inside the cell.

Subscripted assignment dimension mismatch

2 Answers