dpttrf (3p)

Name

dpttrf - compute the L*D*L' factorization of a real symmetric positive definite tridiagonal matrix A

Synopsis

SUBROUTINE DPTTRF(N, D, E, INFO)

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

SUBROUTINE DPTTRF_64(N, D, E, INFO)

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




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

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

SUBROUTINE PTTRF_64(N, D, E, INFO)

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




C INTERFACE
#include <sunperf.h>

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

void dpttrf_64(long n, double *d, double *e, long *info);

Description

Oracle Solaris Studio Performance Library                           dpttrf(3P)



NAME
       dpttrf  - compute the L*D*L' factorization of a real symmetric positive
       definite tridiagonal matrix A


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

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

       SUBROUTINE DPTTRF_64(N, D, E, INFO)

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




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

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

       SUBROUTINE PTTRF_64(N, D, E, INFO)

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




   C INTERFACE
       #include <sunperf.h>

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

       void dpttrf_64(long n, double *d, double *e, long *info);



PURPOSE
       dpttrf computes the L*D*L' factorization of a real  symmetric  positive
       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                        dpttrf(3P)