NAME

csttrf - compute the factorization of a complex Hermitian tridiagonal matrix A

SYNOPSIS

SUBROUTINE CSTTRF( N, L, D, SUBL, IPIV, INFO )

INTEGER INFO, N

REAL D( ∗ )

COMPLEX L( ∗ ), SUBL( ∗ )

#include <sunperf.h>

void csttrf(int n, complex ∗l, float ∗d, complex ∗subl, int ∗info) ;

PURPOSE

CSTTRF computes the L∗D∗L∗∗H factorization of a complex Hermitian tridiagonal matrix A. 
 

ARGUMENTS

N (input) INTEGER
The order of the matrix A.  N >= 0.

L (input/output) COMPLEX array, dimension (N)
On entry, the n-1 subdiagonal elements of the tridiagonal matrix A.  On exit, part of the factorization of A.

D (input/output) REAL array, dimension (N)
On entry, the n diagonal elements of the tridiagonal matrix A.  On exit, the n diagonal elements of the diagonal matrix D from the factorization of A.

SUBL (output) COMPLEX array, dimension (N)
On exit, part of the factorization of A.

IPIV (output) INTEGER array, dimension (N)
On exit, the pivot indices of the factorization.

INFO (output) INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value
> 0:  if INFO = i, D(k,k) is exactly zero.  The factorization has been completed, but the block diagonal matrix D is exactly singular and division by zero will occur if it is used to solve a system of equations.

SunOS 5.0  —  Last change: 10 Dec 1998