.TH ZLARGV 1 "November 2006" " LAPACK auxiliary routine (version 3.1) " " LAPACK auxiliary routine (version 3.1) "
.SH NAME
ZLARGV - a vector of complex plane rotations with real cosines, determined by elements of the complex vectors x and y
.SH SYNOPSIS
.TP 19
SUBROUTINE ZLARGV(
N, X, INCX, Y, INCY, C, INCC )
.TP 19
.ti +4
INTEGER
INCC, INCX, INCY, N
.TP 19
.ti +4
DOUBLE
PRECISION C( * )
.TP 19
.ti +4
COMPLEX*16
X( * ), Y( * )
.SH PURPOSE
ZLARGV 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
.br
( c(i) s(i) ) ( x(i) ) = ( r(i) )
.br
( -conjg(s(i)) c(i) ) ( y(i) ) = ( 0 )
.br
where c(i)**2 + ABS(s(i))**2 = 1
.br
The following conventions are used (these are the same as in ZLARTG,
but differ from the BLAS1 routine ZROTG):
.br
If y(i)=0, then c(i)=1 and s(i)=0.
.br
If x(i)=0, then c(i)=0 and s(i) is chosen so that r(i) is real.
.SH ARGUMENTS
.TP 8
N (input) INTEGER
The number of plane rotations to be generated.
.TP 8
X (input/output) COMPLEX*16 array, dimension (1+(N-1)*INCX)
On entry, the vector x.
On exit, x(i) is overwritten by r(i), for i = 1,...,n.
.TP 8
INCX (input) INTEGER
The increment between elements of X. INCX > 0.
.TP 8
Y (input/output) COMPLEX*16 array, dimension (1+(N-1)*INCY)
On entry, the vector y.
On exit, the sines of the plane rotations.
.TP 8
INCY (input) INTEGER
The increment between elements of Y. INCY > 0.
.TP 8
C (output) DOUBLE PRECISION array, dimension (1+(N-1)*INCC)
The cosines of the plane rotations.
.TP 8
INCC (input) INTEGER
The increment between elements of C. INCC > 0.
.SH 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.