N = 100; 
A = randn(N); % coefficient matrix
M = speye(N); % preconditioner 
b = randn(N, 1);
n = 10; 
kappa = 0;  % 0 <= kappa <= 1
tol = 10^(-7); 
max_it = 3*N;
Q = randn(N, n); 
x = zeros(N, 1); 

[x,err,iter,flag] = mlbicgstab(A,x,b,Q,M,max_it,tol, kappa);