2楼: Originally posted by FMStation at 2016-09-06 20:26:01
https://www.mathworks.com/help/matlab/ref/bicg.html

load west0479;
A = west0479;
b = full(sum(A,2));
tol = 1e-12;
maxit = 20;
= bicg(A,b,tol,maxit);
semilogy(0:maxit,rv0/norm(b),'-o');
xla ...

load west0479;
A = west0479;
b = full(sum(A,2));
tol = 1e-12;
maxit = 20;
[x0,fl0,rr0,it0,rv0] = bicg(A,b,tol,maxit);
semilogy(0:maxit,rv0/norm(b),'-o');
xlabel('Iteration number');
ylabel('Relative residual');

4楼: Originally posted by FMStation at 2016-09-06 21:46:35
http://www.aip.de/groups/soe/local/numres/bookcpdf/c2-7.pdf
void linbcg(unsigned long n, double b[], double x[], int itol, double tol,
int itmax, int *iter, double *err)