f04faf

f04faf © Numerical Algorithms Group, 2002.

Purpose

F04FAF Approximate solution of real symmetric positive-definite tridiagonal simultaneous linear equations, one right-hand side (Black Box)

Synopsis

[d,e,b,ifail] = f04faf(d,e,b<,job,ifail>)

Description

 
 F04FAF solves the equations
 
                               Tx=b,
 
 where T is a real n by n symmetric positive-definite tridiagonal 
 matrix, using a modified symmetric Gaussian elimination algorithm
                        T                                       
 to factorize T as T=MKM , where K is diagonal and M is a matrix 
 of multipliers.
 
 When the input parameter JOB is supplied as 1, then the routine 
 assumes that a previous call to F04FAF has already factorized T; 
 otherwise JOB must be supplied as 0.

Parameters

f04faf

Required Input Arguments:

d (:)                                 real
e (:)                                 real
b (:)                                 real

Optional Input Arguments:                       <Default>

job                                   integer  0
ifail                                 integer  -1

Output Arguments:

d (:)                                 real
e (:)                                 real
b (:)                                 real
ifail                                 integer