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 (realF, realG, realCS, realSN, realR)

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:

September 2012

Definition at line 96 of file slartgp.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

slartgp(3) is an alias of slartgp.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK