SYNOPSIS

SUBROUTINE ZLARTG(

F, G, CS, SN, R )

    

DOUBLE PRECISION CS

    

COMPLEX*16 F, G, R, SN

PURPOSE

ZLARTG generates a plane rotation so that
   [ -SN  CS  ]     [ G ]     [ 0 ]
This is a faster version of the BLAS1 routine ZROTG, 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*16

The first component of vector to be rotated.

G (input) COMPLEX*16

The second component of vector to be rotated.

CS (output) DOUBLE PRECISION

The cosine of the rotation.

SN (output) COMPLEX*16

The sine of the rotation.

R (output) COMPLEX*16

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.