dlartgp.f3
Usage
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 precision f, double precision g, double precision cs, double precision sn, double precision r)
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.
Definition at line 94 of file dlartgp.f.
Releases
4 releases since Debian 7 (Wheezy); the text changed 3 times.