dlartgp.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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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 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.

Date:

December 2016

Definition at line 97 of file dlartgp.f.  

Author

Generated automatically by Doxygen for LAPACK from the source code.


 

Index

NAME
SYNOPSIS
Functions/Subroutines
Function/Subroutine Documentation
subroutine dlartgp (double precision F, double precision G, double precision CS, double precision SN, double precision R)
Author
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