Error: Assignment has more non-singleton rhs dimensions than non-singleton subscripts

Please can someone help. Im trying to run this code

 Hw = zeros(ntrain,ntrain);
    for i = 1:ntrain
        for j = 1:ntrain
            Hw(i,j) = Ytrain(i)*Ytrain(j)*lin(Xtrain(i,:),Xtrain(j,:));
        end
    end

the size of ntrain = 20

but instead the above error message being displayed.

thanks.

Answer 1

[Walter Roberson]

If lin(Xtrain(i,:),Xtrain(j,:)) is returning a vector or array, then the right hand side of the assignment would result in a vector or array, and you would then not be able to store all of that in the single numeric location Hw(i,j) that you have specified.

My guess is that lin() is probably returning a 2 x 2 array, not a scalar.