NAME

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

SYNOPSIS

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

INTEGER INFO, N

DOUBLE PRECISION D( ∗ )

DOUBLE COMPLEX L( ∗ ), SUBL( ∗ )

#include <sunperf.h>

void zsttrf(int n, doublecomplex ∗l, double ∗d, doublecomplex ∗subl, int ∗info) ;

PURPOSE

ZSTTRF computes the factorization of a complex Hermitian tridiagonal matrix A. 
 

ARGUMENTS

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

L (input/output) COMPLEX∗16 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) DOUBLE PRECISION 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 L∗D∗L∗∗H factorization of A.

SUBL (output) COMPLEX∗16 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