dlartg.f (3) - Linux Manuals
NAME
dlartg.f -
SYNOPSIS
Functions/Subroutines
subroutine dlartg (F, G, CS, SN, R)
DLARTG generates a plane rotation with real cosine and real sine.
Function/Subroutine Documentation
subroutine dlartg (double precisionF, double precisionG, double precisionCS, double precisionSN, double precisionR)
DLARTG generates a plane rotation with real cosine and real sine.
Purpose:
-
DLARTG generate 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 BLAS1 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 without doing any floating point operations (saves work in DBDSQR when there are zeros on the diagonal). If F exceeds G in magnitude, CS will be positive.
Parameters:
-
F
F is DOUBLE PRECISION The first component of vector to be rotated.
GG is DOUBLE PRECISION The second component of vector to be rotated.
CSCS is DOUBLE PRECISION The cosine of the rotation.
SNSN is DOUBLE PRECISION The sine of the rotation.
RR 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 98 of file dlartg.f.
Author
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