dpptri (3p)

Name

dpptri - compute the inverse of a real symmetric positive definite matrix A using the Cholesky factorization A = U**T*U or A = L*L**T com- puted by DPPTRF

Synopsis

SUBROUTINE DPPTRI(UPLO, N, A, INFO)

CHARACTER*1 UPLO
INTEGER N, INFO
DOUBLE PRECISION A(*)

SUBROUTINE DPPTRI_64(UPLO, N, A, INFO)

CHARACTER*1 UPLO
INTEGER*8 N, INFO
DOUBLE PRECISION A(*)




F95 INTERFACE
SUBROUTINE PPTRI(UPLO, N, A, INFO)

CHARACTER(LEN=1) :: UPLO
INTEGER :: N, INFO
REAL(8), DIMENSION(:) :: A

SUBROUTINE PPTRI_64(UPLO, N, A, INFO)

CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: N, INFO
REAL(8), DIMENSION(:) :: A




C INTERFACE
#include <sunperf.h>

void dpptri(char uplo, int n, double *a, int *info);

void dpptri_64(char uplo, long n, double *a, long *info);

Description

Oracle Solaris Studio Performance Library                           dpptri(3P)



NAME
       dpptri  -  compute  the  inverse  of a real symmetric positive definite
       matrix A using the Cholesky factorization A = U**T*U or A = L*L**T com-
       puted by DPPTRF


SYNOPSIS
       SUBROUTINE DPPTRI(UPLO, N, A, INFO)

       CHARACTER*1 UPLO
       INTEGER N, INFO
       DOUBLE PRECISION A(*)

       SUBROUTINE DPPTRI_64(UPLO, N, A, INFO)

       CHARACTER*1 UPLO
       INTEGER*8 N, INFO
       DOUBLE PRECISION A(*)




   F95 INTERFACE
       SUBROUTINE PPTRI(UPLO, N, A, INFO)

       CHARACTER(LEN=1) :: UPLO
       INTEGER :: N, INFO
       REAL(8), DIMENSION(:) :: A

       SUBROUTINE PPTRI_64(UPLO, N, A, INFO)

       CHARACTER(LEN=1) :: UPLO
       INTEGER(8) :: N, INFO
       REAL(8), DIMENSION(:) :: A




   C INTERFACE
       #include <sunperf.h>

       void dpptri(char uplo, int n, double *a, int *info);

       void dpptri_64(char uplo, long n, double *a, long *info);



PURPOSE
       dpptri  computes  the  inverse  of  a  real symmetric positive definite
       matrix A using the Cholesky factorization A = U**T*U or A = L*L**T com-
       puted by DPPTRF.


ARGUMENTS
       UPLO (input)
                 = 'U':  Upper triangular factor is stored in A;
                 = 'L':  Lower triangular factor is stored in A.


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


       A (input/output) DOUBLE PRECISION array, dimension (N*(N+1)/2)
                 On entry, the triangular factor U or L from the Cholesky fac-
                 torization A = U**T*U or A = L*L**T, packed columnwise  as  a
                 linear  array.   The  j-th  column of U or L is stored in the
                 array A as follows: if UPLO = 'U', A(i + (j-1)*j/2) =  U(i,j)
                 for  1<=i<=j;  if  UPLO = 'L', A(i + (j-1)*(2n-j)/2) = L(i,j)
                 for j<=i<=n.

                 On exit, the upper  or  lower  triangle  of  the  (symmetric)
                 inverse of A, overwriting the input factor U or L.


       INFO (output)
                 = 0:  successful exit
                 < 0:  if INFO = -i, the i-th argument had an illegal value
                 >  0:  if INFO = i, the (i,i) element of the factor U or L is
                 zero, and the inverse could not be computed.




                                  7 Nov 2015                        dpptri(3P)