DLARTGP (3) Linux Manual Page

NAME

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

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