cungtr (3p)

Name

cungtr - generate a complex unitary matrix Q which is defined as the product of n-1 elementary reflectors of order N, as returned by CHETRD

Synopsis

SUBROUTINE CUNGTR(UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)

CHARACTER*1 UPLO
COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER N, LDA, LWORK, INFO

SUBROUTINE CUNGTR_64(UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)

CHARACTER*1 UPLO
COMPLEX A(LDA,*), TAU(*), WORK(*)
INTEGER*8 N, LDA, LWORK, INFO




F95 INTERFACE
SUBROUTINE UNGTR(UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)

CHARACTER(LEN=1) :: UPLO
COMPLEX, DIMENSION(:) :: TAU, WORK
COMPLEX, DIMENSION(:,:) :: A
INTEGER :: N, LDA, LWORK, INFO

SUBROUTINE UNGTR_64(UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)

CHARACTER(LEN=1) :: UPLO
COMPLEX, DIMENSION(:) :: TAU, WORK
COMPLEX, DIMENSION(:,:) :: A
INTEGER(8) :: N, LDA, LWORK, INFO




C INTERFACE
#include <sunperf.h>

void cungtr(char uplo, int n, complex *a, int lda,  complex  *tau,  int
*info);

void  cungtr_64(char  uplo, long n, complex *a, long lda, complex *tau,
long *info);

Description

Oracle Solaris Studio Performance Library                           cungtr(3P)



NAME
       cungtr  -  generate  a complex unitary matrix Q which is defined as the
       product of n-1 elementary reflectors of order N, as returned by CHETRD


SYNOPSIS
       SUBROUTINE CUNGTR(UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)

       CHARACTER*1 UPLO
       COMPLEX A(LDA,*), TAU(*), WORK(*)
       INTEGER N, LDA, LWORK, INFO

       SUBROUTINE CUNGTR_64(UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)

       CHARACTER*1 UPLO
       COMPLEX A(LDA,*), TAU(*), WORK(*)
       INTEGER*8 N, LDA, LWORK, INFO




   F95 INTERFACE
       SUBROUTINE UNGTR(UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)

       CHARACTER(LEN=1) :: UPLO
       COMPLEX, DIMENSION(:) :: TAU, WORK
       COMPLEX, DIMENSION(:,:) :: A
       INTEGER :: N, LDA, LWORK, INFO

       SUBROUTINE UNGTR_64(UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)

       CHARACTER(LEN=1) :: UPLO
       COMPLEX, DIMENSION(:) :: TAU, WORK
       COMPLEX, DIMENSION(:,:) :: A
       INTEGER(8) :: N, LDA, LWORK, INFO




   C INTERFACE
       #include <sunperf.h>

       void cungtr(char uplo, int n, complex *a, int lda,  complex  *tau,  int
                 *info);

       void  cungtr_64(char  uplo, long n, complex *a, long lda, complex *tau,
                 long *info);



PURPOSE
       cungtr generates a complex unitary matrix Q which  is  defined  as  the
       product of n-1 elementary reflectors of order N, as returned by CHETRD:

       if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),

       if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).


ARGUMENTS
       UPLO (input)
                 = 'U': Upper triangle of  A  contains  elementary  reflectors
                 from  CHETRD;  = 'L': Lower triangle of A contains elementary
                 reflectors from CHETRD.


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


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


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


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


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


       LWORK (input)
                 The  dimension  of the array WORK. LWORK >= N-1.  For optimum
                 performance LWORK >= (N-1)*NB, where NB is the optimal block-
                 size.

                 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                        cungtr(3P)