dgetri (3p)

Name

dgetri - compute the inverse of a matrix using the LU factorization computed by DGETRF

Synopsis

SUBROUTINE DGETRI(N, A, LDA, IPIVOT, WORK, LDWORK, INFO)

INTEGER N, LDA, LDWORK, INFO
INTEGER IPIVOT(*)
DOUBLE PRECISION A(LDA,*), WORK(*)

SUBROUTINE DGETRI_64(N, A, LDA, IPIVOT, WORK, LDWORK, INFO)

INTEGER*8 N, LDA, LDWORK, INFO
INTEGER*8 IPIVOT(*)
DOUBLE PRECISION A(LDA,*), WORK(*)




F95 INTERFACE
SUBROUTINE GETRI(N, A, LDA, IPIVOT, WORK, LDWORK, INFO)

INTEGER :: N, LDA, LDWORK, INFO
INTEGER, DIMENSION(:) :: IPIVOT
REAL(8), DIMENSION(:) :: WORK
REAL(8), DIMENSION(:,:) :: A

SUBROUTINE GETRI_64(N, A, LDA, IPIVOT, WORK, LDWORK, INFO)

INTEGER(8) :: N, LDA, LDWORK, INFO
INTEGER(8), DIMENSION(:) :: IPIVOT
REAL(8), DIMENSION(:) :: WORK
REAL(8), DIMENSION(:,:) :: A




C INTERFACE
#include <sunperf.h>

void dgetri(int n, double *a, int lda, int *ipivot, int *info);

void dgetri_64(long n, double *a, long lda, long *ipivot, long *info);

Description

Oracle Solaris Studio Performance Library                           dgetri(3P)



NAME
       dgetri  -  compute  the  inverse of a matrix using the LU factorization
       computed by DGETRF


SYNOPSIS
       SUBROUTINE DGETRI(N, A, LDA, IPIVOT, WORK, LDWORK, INFO)

       INTEGER N, LDA, LDWORK, INFO
       INTEGER IPIVOT(*)
       DOUBLE PRECISION A(LDA,*), WORK(*)

       SUBROUTINE DGETRI_64(N, A, LDA, IPIVOT, WORK, LDWORK, INFO)

       INTEGER*8 N, LDA, LDWORK, INFO
       INTEGER*8 IPIVOT(*)
       DOUBLE PRECISION A(LDA,*), WORK(*)




   F95 INTERFACE
       SUBROUTINE GETRI(N, A, LDA, IPIVOT, WORK, LDWORK, INFO)

       INTEGER :: N, LDA, LDWORK, INFO
       INTEGER, DIMENSION(:) :: IPIVOT
       REAL(8), DIMENSION(:) :: WORK
       REAL(8), DIMENSION(:,:) :: A

       SUBROUTINE GETRI_64(N, A, LDA, IPIVOT, WORK, LDWORK, INFO)

       INTEGER(8) :: N, LDA, LDWORK, INFO
       INTEGER(8), DIMENSION(:) :: IPIVOT
       REAL(8), DIMENSION(:) :: WORK
       REAL(8), DIMENSION(:,:) :: A




   C INTERFACE
       #include <sunperf.h>

       void dgetri(int n, double *a, int lda, int *ipivot, int *info);

       void dgetri_64(long n, double *a, long lda, long *ipivot, long *info);



PURPOSE
       dgetri computes the inverse of a matrix using the LU factorization com-
       puted by DGETRF.

       This  method  inverts  U and then computes inv(A) by solving the system
       inv(A)*L = inv(U) for inv(A).


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


       A (input/output)
                 On entry, the factors L and U  from  the  factorization  A  =
                 P*L*U  as  computed  by  DGETRF.   On  exit, if INFO = 0, the
                 inverse of the original matrix A.


       LDA (input)
                 The leading dimension of the array A.  LDA >= max(1,N).


       IPIVOT (input)
                 The pivot indices from DGETRF; for  1<=i<=N,  row  i  of  the
                 matrix was interchanged with row IPIVOT(i).


       WORK (workspace)
                 On  exit, if INFO=0, then WORK(1) returns the optimal LDWORK.


       LDWORK (input)
                 The dimension of the array WORK.  LDWORK  >=  max(1,N).   For
                 optimal  performance  LDWORK >= N*NB, where NB is the optimal
                 blocksize returned by ILAENV.

                 If LDWORK = -1, then a workspace query is assumed;  the  rou-
                 tine  only  calculates  the  optimal  size of the WORK array,
                 returns this value as the first entry of the WORK array,  and
                 no error message related to LDWORK is issued by XERBLA.


       INFO (output)
                 = 0:  successful exit
                 < 0:  if INFO = -i, the i-th argument had an illegal value
                 > 0:  if INFO = i, U(i,i) is exactly zero; the matrix is sin-
                 gular and its inverse could not be computed.




                                  7 Nov 2015                        dgetri(3P)