zsttrf(3P) Sun Performance Library zsttrf(3P)NAMEzsttrf - compute the factorization of a complex symmetric tridiagonal
matrix A using the Bunch-Kaufman diagonal pivoting method
SYNOPSIS
SUBROUTINE ZSTTRF(N, L, D, SUBL, IPIV, INFO)
DOUBLE COMPLEX L(*), D(*), SUBL(*)
INTEGER N, INFO
INTEGER IPIV(*)
SUBROUTINE ZSTTRF_64(N, L, D, SUBL, IPIV, INFO)
DOUBLE COMPLEX L(*), D(*), SUBL(*)
INTEGER*8 N, INFO
INTEGER*8 IPIV(*)
F95 INTERFACE
SUBROUTINE STTRF([N], L, D, SUBL, IPIV, [INFO])
COMPLEX(8), DIMENSION(:) :: L, D, SUBL
INTEGER :: N, INFO
INTEGER, DIMENSION(:) :: IPIV
SUBROUTINE STTRF_64([N], L, D, SUBL, IPIV, [INFO])
COMPLEX(8), DIMENSION(:) :: L, D, SUBL
INTEGER(8) :: N, INFO
INTEGER(8), DIMENSION(:) :: IPIV
C INTERFACE
#include <sunperf.h>
void zsttrf(int n, doublecomplex *l, doublecomplex *d, doublecomplex
*subl, int *ipiv, int *info);
void zsttrf_64(long n, doublecomplex *l, doublecomplex *d, doublecom‐
plex *subl, long *ipiv, long *info);
PURPOSEzsttrf computes the L*D*L' factorization of a complex symmetric tridi‐
agonal matrix A using the Bunch-Kaufman diagonal pivoting method.
ARGUMENTS
N (input)
INTEGER
The order of the matrix A. N >= 0.
L (input/output)
COMPLEX array, dimension (N-1)
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-2)
On exit, part of the factorization of A.
IPIV (output)
INTEGER array, dimension (N)
Details of the interchanges and block pivot. If IPIV(K) > 0,
1 by 1 pivot, and if IPIV(K) = K + 1 an interchange done; If
IPIV(K) < 0, 2 by 2 pivot, no interchange required.
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.
6 Mar 2009 zsttrf(3P)