MATLAB Function Reference Volume 1: A - E - Bad Request

icgstab
flag2 is 0 because bicgstab converges to the tolerance of 3.1757e-016 (the
value of relres2) at the sixth iteration (the value of iter2) when
preconditioned by the incomplete LU factorization with a drop tolerance of
1e-6. resvec2(1) = norm(b) and resvec2(13) = norm(b-A*x2). You can
follow the progress of bicgstab by plotting the relative residuals at the halfway
point and end of each iteration starting from the initial estimate (iterate
number 0).
semilogy(0:0.5:iter2,resvec2/norm(b),'-o')
xlabel('iteration number')
ylabel('relative residual')
relative residual
10 0
10 −2
10 −4
10 −6
10 −8
10 −10
10 −12
10 −14
10
0 1 2 3 4 5 6
−16
iteration number
See Also bicg, cgs, gmres, lsqr, luinc, minres, pcg, qmr, symmlq
@ (function handle), \ (backslash)
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