clacrt()

subroutine clacrt	(	integer	N,
		complex, dimension( * )	CX,
		integer	INCX,
		complex, dimension( * )	CY,
		integer	INCY,
		complex	C,
		complex	S
	)

CLACRT performs a linear transformation of a pair of complex vectors.

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Purpose:

 CLACRT performs the operation

    (  c  s )( x )  ==> ( x )
    ( -s  c )( y )      ( y )

 where c and s are complex and the vectors x and y are complex.

Parameters

[in]	N	N is INTEGER The number of elements in the vectors CX and CY.
[in,out]	CX	CX is COMPLEX array, dimension (N) On input, the vector x. On output, CX is overwritten with c*x + s*y.
[in]	INCX	INCX is INTEGER The increment between successive values of CX. INCX <> 0.
[in,out]	CY	CY is COMPLEX array, dimension (N) On input, the vector y. On output, CY is overwritten with -s*x + c*y.
[in]	INCY	INCY is INTEGER The increment between successive values of CY. INCY <> 0.
[in]	C	C is COMPLEX
[in]	S	S is COMPLEX C and S define the matrix [ C S ]. [ -S C ]

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date

December 2016

Definition at line 107 of file clacrt.f.

*
*  -- LAPACK auxiliary routine (version 3.7.0) --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*     December 2016
*
*     .. Scalar Arguments ..
      INTEGER            INCX, INCY, N
      COMPLEX            C, S
*     ..
*     .. Array Arguments ..
      COMPLEX            CX( * ), CY( * )
*     ..
*
* =====================================================================
*
*     .. Local Scalars ..
      INTEGER            I, IX, IY
      COMPLEX            CTEMP
*     ..
*     .. Executable Statements ..
*
      IF( n.LE.0 )
     $   RETURN
      IF( incx.EQ.1 .AND. incy.EQ.1 )
     $   GO TO 20
*
*     Code for unequal increments or equal increments not equal to 1
*
      ix = 1
      iy = 1
      IF( incx.LT.0 )
     $   ix = ( -n+1 )*incx + 1
      IF( incy.LT.0 )
     $   iy = ( -n+1 )*incy + 1
      DO 10 i = 1, n
         ctemp = c*cx( ix ) + s*cy( iy )
         cy( iy ) = c*cy( iy ) - s*cx( ix )
         cx( ix ) = ctemp
         ix = ix + incx
         iy = iy + incy
   10 CONTINUE
      RETURN
*
*     Code for both increments equal to 1
*
   20 CONTINUE
      DO 30 i = 1, n
         ctemp = c*cx( i ) + s*cy( i )
         cy( i ) = c*cy( i ) - s*cx( i )
         cx( i ) = ctemp
   30 CONTINUE
      RETURN