Contents
csttrf - compute the factorization of a complex Hermitian
tridiagonal matrix A
SUBROUTINE CSTTRF(N, L, D, SUBL, IPIV, INFO)
COMPLEX L(*), D(*), SUBL(*)
INTEGER N, INFO
INTEGER IPIV(*)
SUBROUTINE CSTTRF_64(N, L, D, SUBL, IPIV, INFO)
COMPLEX L(*), D(*), SUBL(*)
INTEGER*8 N, INFO
INTEGER*8 IPIV(*)
F95 INTERFACE
SUBROUTINE STTRF([N], L, D, SUBL, IPIV, [INFO])
COMPLEX, DIMENSION(:) :: L, D, SUBL
INTEGER :: N, INFO
INTEGER, DIMENSION(:) :: IPIV
SUBROUTINE STTRF_64([N], L, D, SUBL, IPIV, [INFO])
COMPLEX, DIMENSION(:) :: L, D, SUBL
INTEGER(8) :: N, INFO
INTEGER(8), DIMENSION(:) :: IPIV
C INTERFACE
#include <sunperf.h>
void csttrf(int n, complex *l, complex *d, complex *subl,
int *ipiv, int *info);
void csttrf_64(long n, complex *l, complex *d, complex
*subl, long *ipiv, long *info);
csttrf computes the L*D*L**H factorization of a complex Her-
mitian tridiagonal matrix A.
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 tri-
diagonal matrix A. On exit, part of the factori-
zation of A.
D (input/output)
REAL array, dimension (N)
On entry, the n diagonal elements of the tridiago-
nal 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 ille-
gal 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.