MATLAB saying not enough input arguments.

I am probably missing something completely obvious because I am very new to matlab.

    function y = myrowproduct(A, x)
    %This function computes the pro
    %duct of matrix A by
    %vector x row-wise
    % define m number of rows here to feed into for loop
    [ma,na] = size(A);
    [mx,nx] = size(x);
    % use if statement to check for proper dimensions
    if(na == mx & nx == 1)
    y = zeros(ma,1);   % initialize y vector for n = 1:ma
    y(n) = A(n,:)*x;

    else
    disp('Dimensions of matrices do not match')
    y = [];
    end
  end

Answer 1

[Image Analyst]

Use double &

if (na == mx && nx == 1)

[Ryan]

Ok, I did that. I am getting.

Error in mfile (line 11)
y(n) = A(n,:)*x;

[Image Analyst]

You need

 y(n) = A(n,:) .* x';

to multiply the column elements of row n in y by the row elements in the column vector x.

Answer 2

[Star Strider]

Your value of n is undefined. Not to spoil your fun in troubleshooting your code, but you need a for loop:

          A = rand(4);
          x = rand(4,1);
          na = size(A,1);
          for n = 1:na
              y(n,:) = A(n,:)*x;
          end

Adding the colon in the subscript ( y(n,:) = ... ) forces it to be a column vector, as it should be.

Check your code. Right now, you will only get an empty matrix for y.