CLARTG(3)      LAPACK routine of NEC Numeric Library Collection      CLARTG(3)



NAME
       CLARTG

SYNOPSIS
       SUBROUTINE CLARTG (F, G, CS, SN, R)



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.




ARGUMENTS
           F         (input)
                     F is COMPLEX
                     The first component of vector to be rotated.

           G         (input)
                     G is COMPLEX
                     The second component of vector to be rotated.

           CS        (output)
                     CS is REAL
                     The cosine of the rotation.

           SN        (output)
                     SN is COMPLEX
                     The sine of the rotation.

           R         (output)
                     R is 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.



LAPACK routine                  31 October 2017                      CLARTG(3)