dlartv()

subroutine dlartv	(	integer	n,
		double precision, dimension( * )	x,
		integer	incx,
		double precision, dimension( * )	y,
		integer	incy,
		double precision, dimension( * )	c,
		double precision, dimension( * )	s,
		integer	incc )

DLARTV applies a vector of plane rotations with real cosines and real sines to the elements of a pair of vectors.

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

Purpose:

!>
!> DLARTV applies a vector of real plane rotations to elements of the
!> real vectors x and y. For i = 1,2,...,n
!>
!>    ( x(i) ) := (  c(i)  s(i) ) ( x(i) )
!>    ( y(i) )    ( -s(i)  c(i) ) ( y(i) )
!> 

Parameters

[in]	N	!> N is INTEGER !> The number of plane rotations to be applied. !>
[in,out]	X	!> X is DOUBLE PRECISION array, !> dimension (1+(N-1)*INCX) !> The vector x. !>
[in]	INCX	!> INCX is INTEGER !> The increment between elements of X. INCX > 0. !>
[in,out]	Y	!> Y is DOUBLE PRECISION array, !> dimension (1+(N-1)*INCY) !> The vector y. !>
[in]	INCY	!> INCY is INTEGER !> The increment between elements of Y. INCY > 0. !>
[in]	C	!> C is DOUBLE PRECISION array, dimension (1+(N-1)*INCC) !> The cosines of the plane rotations. !>
[in]	S	!> S is DOUBLE PRECISION array, dimension (1+(N-1)*INCC) !> The sines of the plane rotations. !>
[in]	INCC	!> INCC is INTEGER !> The increment between elements of C and S. INCC > 0. !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 105 of file dlartv.f.

*
*  -- LAPACK auxiliary routine --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*
*     .. Scalar Arguments ..
      INTEGER            INCC, INCX, INCY, N
*     ..
*     .. Array Arguments ..
      DOUBLE PRECISION   C( * ), S( * ), X( * ), Y( * )
*     ..
*
*  =====================================================================
*
*     .. Local Scalars ..
      INTEGER            I, IC, IX, IY
      DOUBLE PRECISION   XI, YI
*     ..
*     .. Executable Statements ..
*
      ix = 1
      iy = 1
      ic = 1
      DO 10 i = 1, n
         xi = x( ix )
         yi = y( iy )
         x( ix ) = c( ic )*xi + s( ic )*yi
         y( iy ) = c( ic )*yi - s( ic )*xi
         ix = ix + incx
         iy = iy + incy
         ic = ic + incc
   10 CONTINUE
      RETURN
*
*     End of DLARTV
*

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