# Tridiagonal System

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 May 21, 2001, 03:47 Tridiagonal System #1 Zhong Lei Guest   Posts: n/a Hi, I wanna if there is any method to efficiently solve a 1-d tridiagonal linear system quation on a vector machine. Any idea? Thanks in advance.

 May 22, 2001, 21:04 Re: Tridiagonal System #2 Ray-zoo Guest   Posts: n/a Solution from tridiagonal linear equations could be computed with Thoma's algorithm, wich is "pivot de Gauss" method for this particular case. Do you really need a vector machine for this ? Please, ask for the algorithm. Best regards, Christophe

 May 22, 2001, 23:04 Re: Tridiagonal System #3 Zhong Lei Guest   Posts: n/a The vector rate of Thoma's algorithm is too low when it runs on a parallel machine. I want to improve the vectorization. of the following do-loop.
do I=1,IMAX
D(I) = D(I) -W(I)*D(I-1)
enddo
Thanks Zhong Lei

 May 24, 2001, 14:18 Re: Tridiagonal System #4 Ray-zoo Guest   Posts: n/a Dear Zhong Lei, Apologises for this late answer due to sparse internet connection. After a read of J.C. Chien's post about vector machines, I could not guess how to vectorize a loop which requires previous iteration step result. As I am mostly newbie to this forum, I can not confirm own opinion that meaningless requests may be a reason for none, or very few answers. If you need running some parallel machines, couldn't you run some domain decomposition method (ddm) ? I had an internet link to those methods, but could not find it before this post. Maybe someone else here knows where to find informations about ddm(s). Yours, Christophe