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Matlab 高斯-赛德尔迭代法怎么用呢?(关键是怎么调用它,附代码)

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Matlab 高斯-赛德尔迭代法怎么用呢?(关键是怎么调用它,附代码)
function X=gseid(A,B,P,delta,max1)
% Input - A is an N x N nonsingular matrix
% - B is an N x 1 matrix
% - P is an N x 1 matrix; the initial guess
% - delta is the tolerance for P
% - max1 is the maximum number of iterations
% Output - X is an N x 1 matrix:the gauss-seidel approximation to
% the solution of AX = B
% NUMERICAL METHODS:Matlab Programs
% (c) 2004 by John H.Mathews and Kurtis D.Fink
% Complementary Software to accompany the textbook:
% NUMERICAL METHODS:Using Matlab,Fourth Edition
% ISBN:0-13-065248-2
% Prentice-Hall Pub.Inc.
% One Lake Street
% Upper Saddle River,NJ 07458
N = length(B);
for k=1:max1
for j=1:N
if j==1
X(1)=(B(1)-A(1,2:N)*P(2:N))/A(1,1);
elseif j==N
X(N)=(B(N)-A(N,1:N-1)*(X(1:N-1))')/A(N,N);
else
%X contains the kth approximations and P the (k-1)st
X(j)=(B(j)-A(j,1:j-1)*X(1:j-1)'-A(j,j+1:N)*P(j+1:N))/A(j,j);
end
end
err=abs(norm(X'-P));
relerr=err/(norm(X)+eps);
P=X';
if (err
A=diag(ones(1,50)*12);
A=A+[[zeros(49,1) -2*diag(ones(1,49))];zeros(1,50)];
A=A+[[zeros(1,49); -2*diag(ones(1,49))] zeros(50,1)];
A=A+[[zeros(48,2) diag(ones(1,48))];zeros(2,50)];
A=A+[[zeros(2,48); diag(ones(1,48))] zeros(50,2)];
b=ones(50,1)*5;
x=gseid(A,b,zeros(50,1),0.001,1000)