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## srotmg()

subroutine srotmg | ( | real | sd1,
|  | real | sd2,
|  | real | sx1,
|  | real | sy1,
|  | real, dimension(5) | sparam )

SROTMG

Purpose:

      !>
      !>    CONSTRUCT THE MODIFIED GIVENS TRANSFORMATION MATRIX H WHICH ZEROS
      !>    THE SECOND COMPONENT OF THE 2-VECTOR  (SQRT(SD1)*SX1,SQRT(SD2)*>    SY2)**T.
      !>    WITH SPARAM(1)=SFLAG, H HAS ONE OF THE FOLLOWING FORMS..
      !>
      !>    SFLAG=-1.E0     SFLAG=0.E0        SFLAG=1.E0     SFLAG=-2.E0
      !>
      !>      (SH11  SH12)    (1.E0  SH12)    (SH11  1.E0)    (1.E0  0.E0)
      !>    H=(          )    (          )    (          )    (          )
      !>      (SH21  SH22),   (SH21  1.E0),   (-1.E0 SH22),   (0.E0  1.E0).
      !>    LOCATIONS 2-4 OF SPARAM CONTAIN SH11,SH21,SH12, AND SH22
      !>    RESPECTIVELY. (VALUES OF 1.E0, -1.E0, OR 0.E0 IMPLIED BY THE
      !>    VALUE OF SPARAM(1) ARE NOT STORED IN SPARAM.)
      !>
      !>    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 SD1 AND SD2.  ALL ACTUAL SCALING OF DATA IS DONE USING GAM.
      !>
      !>

Parameters

  [in,out]

  SD1

      !>          SD1 is REAL
      !>

  [in,out]

  SD2

      !>          SD2 is REAL
      !>

  [in,out]

  SX1

      !>          SX1 is REAL
      !>

  [in]

  SY1

      !>          SY1 is REAL
      !>

  [out]

  SPARAM

      !>          SPARAM is REAL array, dimension (5)
      !>     SPARAM(1)=SFLAG
      !>     SPARAM(2)=SH11
      !>     SPARAM(3)=SH21
      !>     SPARAM(4)=SH12
      !>     SPARAM(5)=SH22
      !>

Author
  Univ. of Tennessee
  Univ. of California Berkeley
  Univ. of Colorado Denver
  NAG Ltd.