function [x,A] = PageRankScores(A_hat,epsilon) % [Note the extra output A here is for MATLAB Grader testing only.] % Use A_hat to form the probability matrix described on the question sheet n = size(A_hat, 1); D = sum(A_hat, 1); P = A_hat./D; TF = isnan(P);%判断是否为NaN P(TF) = ones(n,1)./n;%将NaN都替换为0 % ... then calculate the that into a "PageRank" matrix for this input value % of epsilon ... A = epsilon.*P+(1-epsilon)/n.*ones(n,n); % ... and use power_method to find the dominant eigenvalue & corresponding % eigenvector. x0 = ones(n, 1)/n; [x,lam] = power_method(A,x0); x=x/sum(x); % Ensure x is a probability vector, that is all 0<=x_j<=1 and sum(x)=1. if any(x < 0) || any(x > 1) error('all 0<=x_j<=1'); end if abs(sum(x) - 1) > 1e-6 error('sum(x) should be 1'); end end它报这个错误Double check that the output of your function x is a column vector of size

The error message is telling you to check if the output of your function `x` is a column vector of the expected size. You can use the `size` function to check the size of `x`.

In this case, the expected size is not specified in the error message. However, based on the function signature, we can assume that `x` should be a column vector with the same number of rows as the input matrix `A_hat`. So, you can check if `x` is a column vector and has the same number of rows as `A_hat` by adding the following code at the end of the function:

if ~iscolumn(x) || size(x,1) ~= size(A_hat,1)
    error('The output x is not a column vector of the expected size.');
end

This will throw an error if `x` is not a column vector or has the wrong number of rows.