LAPACK  3.4.1
LAPACK: Linear Algebra PACKage
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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