dlartgp.f man page

dlartgp.f —

Synopsis

Functions/Subroutines

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

Function/Subroutine Documentation

subroutine dlartgp (double precisionF, double precisionG, double precisionCS, double precisionSN, double precisionR)

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

Purpose:

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.

Parameters:

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.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Definition at line 96 of file dlartgp.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK