DLARTGP generates a plane rotation so that


    [  CS  SN  ]  .  [ F ]  =  [ R ]   where CS**2 + SN**2 = 1.


    [ -SN  CS  ]     [ G ]     [ 0 ]


 This is a slower, more accurate version of the Level 1 BLAS 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.


 The sign is chosen so that R >= 0.

F

          F is DOUBLE PRECISION


          The first component of vector to be rotated.

G

          G is DOUBLE PRECISION


          The second component of vector to be rotated.

CS

          CS is DOUBLE PRECISION


          The cosine of the rotation.

SN

          SN is DOUBLE PRECISION


          The sine of the rotation.

R

          R is 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.

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

December 2016