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## clargv()

subroutine clargv | ( | integer | n,
|  | complex, dimension( * ) | x,
|  | integer | incx,
|  | complex, dimension( * ) | y,
|  | integer | incy,
|  | real, dimension( * ) | c,
|  | integer | incc )

CLARGV generates a vector of plane rotations with real cosines and complex sines.

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.

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.
      !>