Defining matrices to solve Ax=b using a(i,j)=-1+2max(i,j) and b(j)=sum(j to n) a(i,j)

So I have to define these matrices and then using some numerical analysis methods to solve the system Ax=b. What I have so far is,

function x=NaiveGauss(n)

A=zeros(n);

for i=1:n

    for j=1:n
        smax=max(i,j);
        A(i,j)=-1+2*smax
    end
end

sum=0;

for j=1:n

    sum=sum(A,2)
end

However I can't get the b matrix to be right. Its supposed to be a nx1 matrix that is the sum of each row but the output keeps telling me that the index exceed matrix dimension. Can anyone possibly help me with this loop? Thanks.

Answer 1

[Sara]

Replace your code with:

summ=0;  
for j=1:n
  summ=sum(A,2)
end

so there is no confusion between the variable summ and the function sum.

[Matthew]

Thanks, I didn't realize Matlab would confuse the two