CLARTG
November 2006
Purpose
CLARTG generates a plane rotation so that
[ CS SN ] [ F ] [ R ]
[ __ ] . [ ] = [ ] where CS**2 + |SN|**2 = 1.
[ -SN CS ] [ G ] [ 0 ]
This is a faster version of the BLAS1 routine CROTG, except for
the following differences:
F and G are unchanged on return.
If G=0, then CS=1 and SN=0.
If F=0, then CS=0 and SN is chosen so that R is real.
[ CS SN ] [ F ] [ R ]
[ __ ] . [ ] = [ ] where CS**2 + |SN|**2 = 1.
[ -SN CS ] [ G ] [ 0 ]
This is a faster version of the BLAS1 routine CROTG, except for
the following differences:
F and G are unchanged on return.
If G=0, then CS=1 and SN=0.
If F=0, then CS=0 and SN is chosen so that R is real.
Arguments
| F |
(input) COMPLEX
The first component of vector to be rotated.
|
| G |
(input) COMPLEX
The second component of vector to be rotated.
|
| CS |
(output) REAL
The cosine of the rotation.
|
| SN |
(output) COMPLEX
The sine of the rotation.
|
| R |
(output) COMPLEX
The nonzero component of the rotated vector.
|
Further Details
3-5-96 - Modified with a new algorithm by W. Kahan and J. Demmel
This version has a few statements commented out for thread safety
(machine parameters are computed on each entry). 10 feb 03, SJH.
This version has a few statements commented out for thread safety
(machine parameters are computed on each entry). 10 feb 03, SJH.