DLARTG(1) LAPACK auxiliary routine (version 3.2) DLARTG(1)NAME
DLARTG - generate a plane rotation so that [ CS SN ]
SYNOPSIS
SUBROUTINE DLARTG( F, G, CS, SN, R )
DOUBLE PRECISION CS, F, G, R, SN
PURPOSE
DLARTG generate a plane rotation so that
[ -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.
ARGUMENTS
F (input) DOUBLE PRECISION
The first component of vector to be rotated.
G (input) DOUBLE PRECISION
The second component of vector to be rotated.
CS (output) DOUBLE PRECISION
The cosine of the rotation.
SN (output) DOUBLE PRECISION
The sine of the rotation.
R (output) 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.
LAPACK auxiliary routine (versioNovember 2008 DLARTG(1)
