zpttrf (3p)

Name

zpttrf - tive definite tridiagonal matrix A

Synopsis

SUBROUTINE ZPTTRF(N, D, E, INFO)

DOUBLE COMPLEX E(*)
INTEGER N, INFO
DOUBLE PRECISION D(*)

SUBROUTINE ZPTTRF_64(N, D, E, INFO)

DOUBLE COMPLEX E(*)
INTEGER*8 N, INFO
DOUBLE PRECISION D(*)




F95 INTERFACE
SUBROUTINE PTTRF(N, D, E, INFO)

COMPLEX(8), DIMENSION(:) :: E
INTEGER :: N, INFO
REAL(8), DIMENSION(:) :: D

SUBROUTINE PTTRF_64(N, D, E, INFO)

COMPLEX(8), DIMENSION(:) :: E
INTEGER(8) :: N, INFO
REAL(8), DIMENSION(:) :: D




C INTERFACE
#include <sunperf.h>

void zpttrf(int n, double *d, doublecomplex *e, int *info);

void zpttrf_64(long n, double *d, doublecomplex *e, long *info);

Description

Oracle Solaris Studio Performance Library                           zpttrf(3P)



NAME
       zpttrf  - compute the L*D*L' factorization of a complex Hermitian posi-
       tive definite tridiagonal matrix A


SYNOPSIS
       SUBROUTINE ZPTTRF(N, D, E, INFO)

       DOUBLE COMPLEX E(*)
       INTEGER N, INFO
       DOUBLE PRECISION D(*)

       SUBROUTINE ZPTTRF_64(N, D, E, INFO)

       DOUBLE COMPLEX E(*)
       INTEGER*8 N, INFO
       DOUBLE PRECISION D(*)




   F95 INTERFACE
       SUBROUTINE PTTRF(N, D, E, INFO)

       COMPLEX(8), DIMENSION(:) :: E
       INTEGER :: N, INFO
       REAL(8), DIMENSION(:) :: D

       SUBROUTINE PTTRF_64(N, D, E, INFO)

       COMPLEX(8), DIMENSION(:) :: E
       INTEGER(8) :: N, INFO
       REAL(8), DIMENSION(:) :: D




   C INTERFACE
       #include <sunperf.h>

       void zpttrf(int n, double *d, doublecomplex *e, int *info);

       void zpttrf_64(long n, double *d, doublecomplex *e, long *info);



PURPOSE
       zpttrf computes the L*D*L' factorization of a complex  Hermitian  posi-
       tive  definite  tridiagonal  matrix  A.   The factorization may also be
       regarded as having the form A = U'*D*U.


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


       D (input/output)
                 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' factorization of A.


       E (input/output)
                 On entry, the (n-1) subdiagonal elements of  the  tridiagonal
                 matrix  A.   On  exit,  the (n-1) subdiagonal elements of the
                 unit bidiagonal factor L from the L*D*L' factorization of  A.
                 E can also be regarded as the superdiagonal of the unit bidi-
                 agonal factor U from the U'*D*U factorization of A.


       INFO (output)
                 = 0: successful exit
                 < 0: if INFO = -k, the k-th argument had an illegal value
                 > 0: if INFO = k, the leading minor of order k is  not  posi-
                 tive  definite; if k < N, the factorization could not be com-
                 pleted, while if k = N, the factorization was completed,  but
                 D(N) = 0.




                                  7 Nov 2015                        zpttrf(3P)