# MATLAB: Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.

for loop

I am trying to run a simple for loop to create a matrix that made up of 2n vectors of random numbers that all sum to 1. I have the proper code for making a singular vector, but am having issues with my for loop. The resulting matrix should be of size 2nx2n the loop is 2n long and the vectors are 2n long, so I don't understand why the sides are mismatched.
``r = rand(1,2.*n); %2n random numbers that will make up the vectors in Pr = r/sum(r); %normalize the vector to 1thesum = sum(r); %check that the vector sums to 1for i = 1:2.*n    P(i) = r./sum(r); %repeat random vectors 2.*n times to create the matrix of probabilitiesend``

``n = 5;P = zeros(2 * n, 2 * n);for row = 1 : 2 * n	thisRow = rand(1, 2.*n); % 2n random numbers that will make up the rows of P	thisRow = thisRow / sum(thisRow);	% Normalize the sum of the row vector to 1	% Assign this row to P	P(row, :) = thisRow; % Stuff this row into PendP % Report to command window.% Check that all rows sum to 1rowSums = sum(P, 2) % Sum each row, going across columns``