BLAS/SRC/drotmg.f(3)

NAME
BLAS/SRC/drotmg.f

SYNOPSIS

  Functions/Subroutines
subroutine drotmg (dd1, dd2, dx1, dy1, dparam)
DROTMG

Function/Subroutine Documentation

  subroutine drotmg (double precision dd1, double precision dd2, double precision dx1, double precision dy1, double precision, dimension(5) dparam)

DROTMG

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.
    !>
    !>

Parameters
    DD1

    !>          DD1 is DOUBLE PRECISION
    !>

    DD2

    !>          DD2 is DOUBLE PRECISION
    !>

    DX1

    !>          DX1 is DOUBLE PRECISION
    !>

    DY1

    !>          DY1 is DOUBLE PRECISION
    !>

    DPARAM

    !>          DPARAM is DOUBLE PRECISION array, dimension (5)
    !>     DPARAM(1)=DFLAG
    !>     DPARAM(2)=DH11
    !>     DPARAM(3)=DH21
    !>     DPARAM(4)=DH12
    !>     DPARAM(5)=DH22
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 89 of file drotmg.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.