Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
DLAREF(l)			       )			     DLAREF(l)

NAME
       DLAREF  - applie	one or several Householder reflectors of size 3	to one
       or two matrices (if column is specified)	on either their	rows  or  col-
       umns

SYNOPSIS
       SUBROUTINE DLAREF( TYPE,	 A,  LDA,  WANTZ, Z, LDZ, BLOCK, IROW1,	ICOL1,
			  ISTART, ISTOP, ITMP1,	ITMP2, LILOZ, LIHIZ, VECS, V2,
			  V3, T1, T2, T3 )

	   LOGICAL	  BLOCK, WANTZ

	   CHARACTER	  TYPE

	   INTEGER	  ICOL1, IROW1,	ISTART,	ISTOP, ITMP1, ITMP2, LDA, LDZ,
			  LIHIZ, LILOZ

	   DOUBLE	  PRECISION T1,	T2, T3,	V2, V3

	   DOUBLE	  PRECISION A( LDA, * ), VECS( * ), Z( LDZ, * )

PURPOSE
       DLAREF applies one or several Householder reflectors of size 3  to  one
       or  two	matrices (if column is specified) on either their rows or col-
       umns.

ARGUMENTS
       TYPE    (global input) CHARACTER*1
	       If 'R': Apply reflectors	to the rows of the matrix (apply  from
	       left)  Otherwise: Apply reflectors to the columns of the	matrix
	       Unchanged on exit.

       A       (global input/output) DOUBLE PRECISION array, (LDA,*)
	       On entry, the matrix to receive the reflections.	  The  updated
	       matrix on exit.

       LDA     (local input) INTEGER
	       On entry, the leading dimension of A.  Unchanged	on exit.

       WANTZ   (global input) LOGICAL
	       If  .TRUE., then	apply any column reflections to	Z as well.  If
	       .FALSE.,	then do	no additional work on Z.

       Z       (global input/output) DOUBLE PRECISION array, (LDZ,*)
	       On entry, the second  matrix  to	 receive  column  reflections.
	       This is changed only if WANTZ is	set.

       LDZ     (local input) INTEGER
	       On entry, the leading dimension of Z.  Unchanged	on exit.

       BLOCK   (global input) LOGICAL
	       If .TRUE., then apply several reflectors	at once	and read their
	       data from the VECS array.  If .FALSE., apply the	single reflec-
	       tor given by V2,	V3, T1,	T2, and	T3.

       IROW1   (local input/output) INTEGER
	       On entry, the local row element of A.  Undefined	on output.

       ICOL1   (local input/output) INTEGER
	       On entry, the local column element of A.	 Undefined on output.

       ISTART  (global input) INTEGER
	       Specifies the "number" of the first reflector.  This is used as
	       an index	into VECS if BLOCK is set.  ISTART is ignored if BLOCK
	       is .FALSE..

       ISTOP   (global input) INTEGER
	       Specifies  the "number" of the last reflector.  This is used as
	       an index	into VECS if BLOCK is set.  ISTOP is ignored if	 BLOCK
	       is .FALSE..

       ITMP1   (local input) INTEGER
	       Starting	 range into A.	For rows, this is the local first col-
	       umn.  For columns, this is the local first row.

       ITMP2   (local input) INTEGER
	       Ending range into A.  For rows, this is the local last  column.
	       For columns, this is the	local last row.

	       LILOZ  LIHIZ    (local input) INTEGER These serve the same pur-
	       pose as ITMP1,ITMP2 but for Z when WANTZ	is set.

       VECS    (global input) DOUBLE PRECISION array of	size 3*N (matrix
	       size) This holds	the size 3 reflectors one  after  another  and
	       this is only accessed when BLOCK	is .TRUE.

	       V2 V3 T1	T2 T3	   (global input/output) DOUBLE	PRECISION This
	       holds information on a single size 3 Householder	reflector  and
	       is  read	 when  BLOCK is	.FALSE., and overwritten when BLOCK is
	       .TRUE.

	       Implemented by:	G. Henry, November 17, 1996

ScaLAPACK version 1.7		13 August 2001			     DLAREF(l)

NAME | SYNOPSIS | PURPOSE | ARGUMENTS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=dlaref&manpath=FreeBSD+12.1-RELEASE+and+Ports>

home | help