DROTMG(1)

NAME
LAPACK-3 - CONSTRUCT THE MODIFIED GIVENS TRANSFORMATION MATRIX H WHICH ZEROS THE SECOND COMPONENT OF THE 2-VECTOR (DSQRT(DD1)*DX1,DSQRT(DD2)*

SYNOPSIS

SUBROUTINE DROTMG(DD1,DD2,DX1,DY1,DPARAM)

DOUBLE
    PRECISION DD1,DD2,DX1,DY1

DOUBLE
    PRECISION DPARAM(5)

PURPOSE
   CONSTRUCT THE MODIFIED GIVENS TRANSFORMATION MATRIX H WHICH ZEROS
   THE SECOND COMPONENT OF THE 2-VECTOR (DSQRT(DD1)*DX1,DSQRT(DD2)*
    DY2)**T.
    WITH DPARAM(1)=DFLAG, H HAS ONE OF THE FOLLOWING FORMS..
    DFLAG=-1.D0 DFLAG=0.D0 DFLAG=1.D0 DFLAG=-2.D0
      (DH11 DH12) (1.D0 DH12) (DH11 1.D0) (1.D0 0.D0)
    H=( ) ( ) ( ) ( )
      (DH21 DH22), (DH21 1.D0), (-1.D0 DH22), (0.D0 1.D0).
    LOCATIONS 2-4 OF DPARAM CONTAIN DH11, DH21, DH12, AND DH22
    RESPECTIVELY. (VALUES OF 1.D0, -1.D0, OR 0.D0 IMPLIED BY THE
    VALUE OF DPARAM(1) ARE NOT STORED IN DPARAM.)
    THE VALUES OF GAMSQ AND RGAMSQ SET IN THE DATA STATEMENT MAY BE
    INEXACT. THIS IS OK AS THEY ARE ONLY USED FOR TESTING THE SIZE
    OF DD1 AND DD2. ALL ACTUAL SCALING OF DATA IS DONE USING GAM.

ARGUMENTS

DD1    (input/output) DOUBLE PRECISION

DD2    (input/output) DOUBLE PRECISION

DX1    (input/output) DOUBLE PRECISION

DY1    (input) DOUBLE PRECISION
     DPARAM (input/output) DOUBLE PRECISION array, dimension 5
     DPARAM(1)=DFLAG
     DPARAM(2)=DH11
     DPARAM(3)=DH21
     DPARAM(4)=DH12
     DPARAM(5)=DH22