slartgp.f man page

slartgp.f

Synopsis

Functions/Subroutines

subroutine slartgp (F, G, CS, SN, R)
SLARTGP generates a plane rotation so that the diagonal is nonnegative.

Function/Subroutine Documentation

subroutine slartgp (real F, real G, real CS, real SN, real R)

SLARTGP generates a plane rotation so that the diagonal is nonnegative.  

Purpose:

 SLARTGP 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 SROTG,
 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.
Parameters:

F

          F is REAL
          The first component of vector to be rotated.

G

          G is REAL
          The second component of vector to be rotated.

CS

          CS is REAL
          The cosine of the rotation.

SN

          SN is REAL
          The sine of the rotation.

R

          R is REAL
          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.
Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

December 2016

Definition at line 97 of file slartgp.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page slartgp(3) is an alias of slartgp.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK