jacobi method using one for loop

Question

Isaac Al-rai 2018-2-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/383279-jacobi-method-using-one-for-loop

编辑： Isaac Al-rai 2018-2-17

I have a code written that will use jacobi method to solve a problem but in my numerical methods class I need to be able to perfrom this function in one loop. Here is my current code:

if true
  % code
function X=jacobi(A,B,P,delta,max1)
N = length(B);
for k=1:max1
 for j=1:N
    X(j)=(B(j)-A(j,[1:j-1,j+1:N])*P([1:j-1,j+1:N]))/A(j,j);
 end
 err=abs(norm(X'-P));
 relerr=err/(norm(X)+eps);
 P=X';
    if (err<delta)||(relerr<delta)
   break
 end
end
X=X';
end
end

And this seems to work. It defines X(j) and spits out values from 1 to the length of B(100). Now I need to find a way to make this run using only ONE for loop. so I need to probably get rid of the j indices and replace it with k. Anyone know how I can make this work?

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Answer 1

Isaac Al-rai 2018-2-17

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/383279-jacobi-method-using-one-for-loop#answer_305690

编辑：Isaac Al-rai 2018-2-17

在 MATLAB Online 中打开

I first tried to replace the second for loop with

if true
  % code
j=eye(100)
end

And adjusted my code to look like this

if true
  % code
function X=jacobian(A,B,P,delta,max1)
N = length(B);
for k=1:max1
 j=eye(100)
    X(1:j)=(B(1:j)-A(1:j,[1:j-1,j+1:N])*P([1:j-1,j+1:N]))/A(1:j,1:j);
 end
 err=abs(norm(X'-P));
 relerr=err/(norm(X)+eps);
 P=X';
    if (err<delta)||(relerr<delta)
   RETURN
    end
X=X';
end
end