what is this error? and what is my mistake?

I want to make Gauss Seidel Relaxation matlab code.

there is my script. and i dont know what is problem..

plz answer.. to make an right script.

function [x,ea,iter]=GaussSeidelR(A,b,lamda,es,maxit)

% GaussSeidel: Gauss Seidel Method

% x=GaussSeidel(A,b): Gauss Seidel without relaxation % input:

% A= coefficient matrix % b=right hand side vector % es=stop criterion (default=0.00001%) % maxit=max iteration (default = 50)

% output:

% x=solution vector

if nargin<2, error('at least 2 input arguments requried'),end if nargin<5 | isempty(maxit), maxit=50; end if nargin<4 | isempty(es), es=0.00001; end if nargin<3 | isempty(lamda), lamda=1; end

[m,n]=size(A); if m~=n, error('Matrix A must be square'); end C=A; for i=1:n C(i,i)=0; x(i)=0; end x=x'; for i=1:n C(i,1:n)=C(i,1:n)/A(i,i); end for i=1:n d(i)=b(i)/A(i,i); end iter=0; while(1)

    xold=x; 
    for i=1:n
        x(i)=d(i)-C(i,:)*x;
        x(i)=lamda*x(i)+(1-lamda)*xold;

      if x(i)~=0
          ea(i)=abs((x(i)-xold(i))/x(i))*100;
      end
    end
    iter=iter+1;
    if max(ea)<=es | iter>=maxit, break, end
end

*|error massage

>> [x,ea,iter]=GaussSeidelR(A,b,lamda) ??? In an assignment A(I) = B, the number of elements in B and I must be the same.

Error in ==> GaussSeidelR at 38 x(i)=lamda*x(i)+(1-lamda)*xold;|*

Answer 1

[Iain]

The error is that you are trying to put more than ONE element into a single element of an array.

Either change x(i) to x(i,:) or x(:,i), OR ensure that lambda is a scalar value.