dlartg.f man page

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.

Referenced By

The man page dlartg(3) is an alias of dlartg.f(3).

Sat Jun 24 2017 Version 3.7.1 LAPACK