---
name: "clartg"
section: "3lapack"
platform: "linux"
package: "liblapack-doc"
version: "3.2.1-8"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/clartg/3lapack"
---

# clartg(3lapack)

generates a plane rotation so that \[ CS SN \] \[ F \] \[ R \] \[ \_\_ \]

## NAME

CLARTG - generates a plane rotation so that   \[ CS SN \] \[ F \] \[ R \]  \[ \_\_ \]

## SYNOPSIS

- SUBROUTINE CLARTG(

  F, G, CS, SN, R )

- REAL

  CS

- COMPLEX

  F, G, R, SN

## PURPOSE

CLARTG generates a plane rotation so that\
    \[ -SN  CS  \]     \[ G \]     \[ 0 \]\
 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.