dlartg.f

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

dlartg.f  

SYNOPSIS


 

Functions/Subroutines


subroutine dlartg (F, G, CS, SN, R)
DLARTG generates a plane rotation with real cosine and real sine.  

Function/Subroutine Documentation

 

subroutine dlartg (double precision F, double precision G, double precision CS, double precision SN, double precision R)

DLARTG generates a plane rotation with real cosine and real sine.

Purpose:

 DLARTG generate a plane rotation so that

    [  CS  SN  ]  .  [ F ]  =  [ R ]   where CS**2 + SN**2 = 1.
    [ -SN  CS  ]     [ G ]     [ 0 ]

 This is a slower, more accurate version of the BLAS1 routine DROTG,
 with the following other differences:
    F and G are unchanged on return.
    If G=0, then CS=1 and SN=0.
    If F=0 and (G .ne. 0), then CS=0 and SN=1 without doing any
       floating point operations (saves work in DBDSQR when
       there are zeros on the diagonal).

 If F exceeds G in magnitude, CS will be positive.


 

Parameters:

F

          F is DOUBLE PRECISION
          The first component of vector to be rotated.


G

          G is DOUBLE PRECISION
          The second component of vector to be rotated.


CS

          CS is DOUBLE PRECISION
          The cosine of the rotation.


SN

          SN is DOUBLE PRECISION
          The sine of the rotation.


R

          R is DOUBLE PRECISION
          The nonzero component of the rotated vector.

  This version has a few statements commented out for thread safety
  (machine parameters are computed on each entry). 10 feb 03, SJH.


 

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

December 2016

Definition at line 99 of file dlartg.f.  

Author

Generated automatically by Doxygen for LAPACK from the source code.


 

Index

NAME
SYNOPSIS
Functions/Subroutines
Function/Subroutine Documentation
subroutine dlartg (double precision F, double precision G, double precision CS, double precision SN, double precision R)
Author
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