dorghr (3p)

Name

dorghr - generate a real orthogonal matrix Q which is defined as the product of IHI-ILO elementary reflectors of order N, as returned by DGEHRD

Synopsis

SUBROUTINE DORGHR(N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO)

INTEGER N, ILO, IHI, LDA, LWORK, INFO
DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*)

SUBROUTINE DORGHR_64(N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO)

INTEGER*8 N, ILO, IHI, LDA, LWORK, INFO
DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*)




F95 INTERFACE
SUBROUTINE ORGHR(N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO)

INTEGER :: N, ILO, IHI, LDA, LWORK, INFO
REAL(8), DIMENSION(:) :: TAU, WORK
REAL(8), DIMENSION(:,:) :: A

SUBROUTINE ORGHR_64(N, ILO, IHI, A, LDA, TAU, WORK, LWORK,
INFO)

INTEGER(8) :: N, ILO, IHI, LDA, LWORK, INFO
REAL(8), DIMENSION(:) :: TAU, WORK
REAL(8), DIMENSION(:,:) :: A




C INTERFACE
#include <sunperf.h>

void  dorghr(int  n, int ilo, int ihi, double *a, int lda, double *tau,
int *info);

void dorghr_64(long n, long ilo, long ihi, double *a, long lda,  double
*tau, long *info);

Description

Oracle Solaris Studio Performance Library                           dorghr(3P)



NAME
       dorghr  -  generate  a real orthogonal matrix Q which is defined as the
       product of IHI-ILO elementary reflectors of order  N,  as  returned  by
       DGEHRD


SYNOPSIS
       SUBROUTINE DORGHR(N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO)

       INTEGER N, ILO, IHI, LDA, LWORK, INFO
       DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*)

       SUBROUTINE DORGHR_64(N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO)

       INTEGER*8 N, ILO, IHI, LDA, LWORK, INFO
       DOUBLE PRECISION A(LDA,*), TAU(*), WORK(*)




   F95 INTERFACE
       SUBROUTINE ORGHR(N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO)

       INTEGER :: N, ILO, IHI, LDA, LWORK, INFO
       REAL(8), DIMENSION(:) :: TAU, WORK
       REAL(8), DIMENSION(:,:) :: A

       SUBROUTINE ORGHR_64(N, ILO, IHI, A, LDA, TAU, WORK, LWORK,
              INFO)

       INTEGER(8) :: N, ILO, IHI, LDA, LWORK, INFO
       REAL(8), DIMENSION(:) :: TAU, WORK
       REAL(8), DIMENSION(:,:) :: A




   C INTERFACE
       #include <sunperf.h>

       void  dorghr(int  n, int ilo, int ihi, double *a, int lda, double *tau,
                 int *info);

       void dorghr_64(long n, long ilo, long ihi, double *a, long lda,  double
                 *tau, long *info);



PURPOSE
       dorghr  generates  a  real  orthogonal matrix Q which is defined as the
       product of IHI-ILO elementary reflectors of order  N,  as  returned  by
       DGEHRD:

       Q = H(ilo) H(ilo+1) . . . H(ihi-1).


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


       ILO (input)
                 ILO and IHI must have the same values as in the previous call
                 of DGEHRD. Q is equal to the unit matrix except in the subma-
                 trix Q(ilo+1:ihi,ilo+1:ihi).  1 <= ILO <= IHI <= N, if N > 0;
                 ILO=1 and IHI=0, if N=0.


       IHI (input)
                 See the description of ILO.


       A (input/output)
                 On entry, the vectors which define the elementary reflectors,
                 as returned by DGEHRD.  On exit, the N-by-N orthogonal matrix
                 Q.


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


       TAU (input)
                 TAU(i) must contain  the  scalar  factor  of  the  elementary
                 reflector H(i), as returned by DGEHRD.


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


       LWORK (input)
                 The dimension of the array WORK. LWORK >= IHI-ILO.  For opti-
                 mum performance LWORK >= (IHI-ILO)*NB, where NB is the  opti-
                 mal blocksize.

                 If LWORK = -1, then a workspace query is assumed; the routine
                 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 LWORK is issued by XERBLA.


       INFO (output)
                 = 0:  successful exit
                 < 0:  if INFO = -i, the i-th argument had an illegal value




                                  7 Nov 2015                        dorghr(3P)