zlartg.f File Reference

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Functions/Subroutines
subroutine	zlartg (F, G, CS, SN, R)
	ZLARTG generates a plane rotation with real cosine and complex sine.

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Function/Subroutine Documentation

subroutine zlartg	(	complex*16	F,
		complex*16	G,
		double precision	CS,
		complex*16	SN,
		complex*16	R
	)

ZLARTG generates a plane rotation with real cosine and complex sine.

Download ZLARTG + dependencies [TGZ] [ZIP] [TXT]

Purpose:

 ZLARTG generates a plane rotation so that

    [  CS  SN  ]     [ F ]     [ R ]
    [  __      ]  .  [   ]  =  [   ]   where CS**2 + |SN|**2 = 1.
    [ -SN  CS  ]     [ G ]     [ 0 ]

 This is a faster version of the BLAS1 routine ZROTG, except for
 the following differences:
    F and G are unchanged on return.
    If G=0, then CS=1 and SN=0.
    If F=0, then CS=0 and SN is chosen so that R is real.

Parameters:

[in]	F	F is COMPLEX*16 The first component of vector to be rotated.
[in]	G	G is COMPLEX*16 The second component of vector to be rotated.
[out]	CS	CS is DOUBLE PRECISION The cosine of the rotation.
[out]	SN	SN is COMPLEX*16 The sine of the rotation.
[out]	R	R is COMPLEX*16 The nonzero component of the rotated vector.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

September 2012

Further Details:

  3-5-96 - Modified with a new algorithm by W. Kahan and J. Demmel

  This version has a few statements commented out for thread safety
  (machine parameters are computed on each entry). 10 feb 03, SJH.

Definition at line 104 of file zlartg.f.

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