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## drotm()

subroutine drotm | ( | integer | n,
|  | double precision, dimension(*) | dx,
|  | integer | incx,
|  | double precision, dimension(*) | dy,
|  | integer | incy,
|  | double precision, dimension(5) | dparam )

DROTM

Purpose:

      !>
      !>    APPLY THE MODIFIED GIVENS TRANSFORMATION, H, TO THE 2 BY N MATRIX
      !>
      !>    (DX**T) , WHERE **T INDICATES TRANSPOSE. THE ELEMENTS OF DX ARE IN
      !>    (DY**T)
      !>
      !>    DX(LX+I*INCX), I = 0 TO N-1, WHERE LX = 1 IF INCX .GE. 0, ELSE
      !>    LX = (-INCX)*N, AND SIMILARLY FOR SY USING LY AND INCY.
      !>    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).
      !>    SEE DROTMG FOR A DESCRIPTION OF DATA STORAGE IN DPARAM.
      !>

Parameters

  [in]

  N

      !>          N is INTEGER
      !>         number of elements in input vector(s)
      !>

  [in,out]

  DX

      !>          DX is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
      !>

  [in]

  INCX

      !>          INCX is INTEGER
      !>         storage spacing between elements of DX
      !>

  [in,out]

  DY

      !>          DY is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
      !>

  [in]

  INCY

      !>          INCY is INTEGER
      !>         storage spacing between elements of DY
      !>

  [in]

  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.