dlarz (3p)

Name

dlarz - N matrix C, from either the left or the right

Synopsis

SUBROUTINE DLARZ(SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)

CHARACTER*1 SIDE
INTEGER M, N, L, INCV, LDC
DOUBLE PRECISION TAU
DOUBLE PRECISION V(*), C(LDC,*), WORK(*)

SUBROUTINE DLARZ_64(SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)

CHARACTER*1 SIDE
INTEGER*8 M, N, L, INCV, LDC
DOUBLE PRECISION TAU
DOUBLE PRECISION V(*), C(LDC,*), WORK(*)




F95 INTERFACE
SUBROUTINE LARZ(SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)

CHARACTER(LEN=1) :: SIDE
INTEGER :: M, N, L, INCV, LDC
REAL(8) :: TAU
REAL(8), DIMENSION(:) :: V, WORK
REAL(8), DIMENSION(:,:) :: C

SUBROUTINE LARZ_64(SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)

CHARACTER(LEN=1) :: SIDE
INTEGER(8) :: M, N, L, INCV, LDC
REAL(8) :: TAU
REAL(8), DIMENSION(:) :: V, WORK
REAL(8), DIMENSION(:,:) :: C




C INTERFACE
#include <sunperf.h>

void dlarz(char side, int m, int n, int l, double *v, int incv,  double
tau, double *c, int ldc);

void  dlarz_64(char side, long m, long n, long l, double *v, long incv,
double tau, double *c, long ldc);

Description

Oracle Solaris Studio Performance Library                            dlarz(3P)



NAME
       dlarz  - apply a real elementary reflector H to a real M-by-N matrix C,
       from either the left or the right


SYNOPSIS
       SUBROUTINE DLARZ(SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)

       CHARACTER*1 SIDE
       INTEGER M, N, L, INCV, LDC
       DOUBLE PRECISION TAU
       DOUBLE PRECISION V(*), C(LDC,*), WORK(*)

       SUBROUTINE DLARZ_64(SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)

       CHARACTER*1 SIDE
       INTEGER*8 M, N, L, INCV, LDC
       DOUBLE PRECISION TAU
       DOUBLE PRECISION V(*), C(LDC,*), WORK(*)




   F95 INTERFACE
       SUBROUTINE LARZ(SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)

       CHARACTER(LEN=1) :: SIDE
       INTEGER :: M, N, L, INCV, LDC
       REAL(8) :: TAU
       REAL(8), DIMENSION(:) :: V, WORK
       REAL(8), DIMENSION(:,:) :: C

       SUBROUTINE LARZ_64(SIDE, M, N, L, V, INCV, TAU, C, LDC, WORK)

       CHARACTER(LEN=1) :: SIDE
       INTEGER(8) :: M, N, L, INCV, LDC
       REAL(8) :: TAU
       REAL(8), DIMENSION(:) :: V, WORK
       REAL(8), DIMENSION(:,:) :: C




   C INTERFACE
       #include <sunperf.h>

       void dlarz(char side, int m, int n, int l, double *v, int incv,  double
                 tau, double *c, int ldc);

       void  dlarz_64(char side, long m, long n, long l, double *v, long incv,
                 double tau, double *c, long ldc);



PURPOSE
       dlarz applies a real elementary reflector H to a real M-by-N matrix  C,
       from either the left or the right. H is represented in the form

             H = I - tau * v * v'

       where tau is a real scalar and v is a real vector.

       If tau = 0, then H is taken to be the unit matrix.

       H is a product of k elementary reflectors as returned by DTZRZF.


ARGUMENTS
       SIDE (input)
                 = 'L': form  H * C
                 = 'R': form  C * H


       M (input) The number of rows of the matrix C.


       N (input) The number of columns of the matrix C.


       L (input) The number of entries of the vector V containing the meaning-
                 ful part of the Householder vectors.  If SIDE = 'L', M  >=  L
                 >= 0, if SIDE = 'R', N >= L >= 0.


       V (input) DOUBLE  PRECISION  array of dimension (1+(L-1)*abs(INCV)) The
                 vector v in the representation of H as returned by DTZRZF.  V
                 is not used if TAU = 0.


       INCV (input)
                 The increment between elements of v. INCV <> 0.


       TAU (input)
                 The value tau in the representation of H.


       C (input/output)
                 On  entry, the M-by-N matrix C.  On exit, C is overwritten by
                 the matrix H * C if SIDE = 'L', or C * H if SIDE = 'R'.


       LDC (input)
                 The leading dimension of the array C. LDC >= max(1,M).


       WORK (workspace)
                 (N) if SIDE = 'L' or (M) if SIDE = 'R'

FURTHER DETAILS
       Based on contributions by
         A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA




                                  7 Nov 2015                         dlarz(3P)