LAPACK  3.5.0
LAPACK: Linear Algebra PACKage
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srotmg.f File Reference

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Functions/Subroutines

subroutine srotmg (SD1, SD2, SX1, SY1, SPARAM)
 SROTMG More...
 

Function/Subroutine Documentation

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
[in,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.
Date
November 2011

Definition at line 91 of file srotmg.f.

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