srotmg.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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NAME

srotmg.f

SYNOPSIS

Functions/Subroutines

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

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:

SD1

          SD1 is REAL

SD2

          SD2 is REAL

SX1

          SX1 is REAL

SY1

          SY1 is REAL

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 2017

Definition at line 92 of file srotmg.f.

Author

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