Posted by Henk van der Vorst on May 23, 1998 at 15:36:09:
In Reply to: Bi-CGSTAB.m posted by Barya Venansius on May 04, 1998 at 12:12:16:
: In the routine bicgstab.m under mltemplates.shar,
: r_tld is constant throughout the iterations.
: I can not figure out why this is so.
: I personally expected it to change at every iteration.
MY COMMENT: The vector r_tld should be kept
constant throughout the iteration. In Bi-CG this
vector is changed, but the key trick in Bi-CGSTAB
is that the changes to r_tld are transferred to
r. This makes the method potentially faster than
Bi-CG. The vector r_tld is still required in
order to be able to computed several innerproducts.
Further information on B-CGSTAB may be obtained
from my lecture notes on my WEB page:
good luck with Bi-CGSTAB,
Henk van der Vorst