clargv.f File Reference

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Functions/Subroutines
subroutine	CLARGV (N, X, INCX, Y, INCY, C, INCC)
	CLARGV

---

Function/Subroutine Documentation

subroutine CLARGV	(	INTEGER	N,
		COMPLEX, dimension( * )	X,
		INTEGER	INCX,
		COMPLEX, dimension( * )	Y,
		INTEGER	INCY,
		REAL, dimension( * )	C,
		INTEGER	INCC
	)

CLARGV

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

Purpose:

 CLARGV generates a vector of complex plane rotations with real
 cosines, determined by elements of the complex vectors x and y.
 For i = 1,2,...,n

    (        c(i)   s(i) ) ( x(i) ) = ( r(i) )
    ( -conjg(s(i))  c(i) ) ( y(i) ) = (   0  )

    where c(i)**2 + ABS(s(i))**2 = 1

 The following conventions are used (these are the same as in CLARTG,
 but differ from the BLAS1 routine CROTG):
    If y(i)=0, then c(i)=1 and s(i)=0.
    If x(i)=0, then c(i)=0 and s(i) is chosen so that r(i) is real.
 

Parameters:

[in]	N	N is INTEGER The number of plane rotations to be generated.
[in,out]	X	X is COMPLEX array, dimension (1+(N-1)*INCX) On entry, the vector x. On exit, x(i) is overwritten by r(i), for i = 1,...,n.
[in]	INCX	INCX is INTEGER The increment between elements of X. INCX > 0.
[in,out]	Y	Y is COMPLEX array, dimension (1+(N-1)*INCY) On entry, the vector y. On exit, the sines of the plane rotations.
[in]	INCY	INCY is INTEGER The increment between elements of Y. INCY > 0.
[out]	C	C is REAL array, dimension (1+(N-1)*INCC) The cosines of the plane rotations.
[in]	INCC	INCC is INTEGER The increment between elements of C. INCC > 0.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Further Details:

  6-6-96 - 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 123 of file clargv.f.

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