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SUBROUTINE ZDROT( N, CX, INCX, CY, INCY, C, S )
*
* applies a plane rotation, where the cos and sin (c and s) are real
* and the vectors cx and cy are complex.
* jack dongarra, linpack, 3/11/78.
*
* .. Scalar Arguments ..
INTEGER INCX, INCY, N
DOUBLE PRECISION C, S
* ..
* .. Array Arguments ..
COMPLEX*16 CX( * ), CY( * )
*
* =====================================================================
* ..
* .. Local Scalars ..
INTEGER I, IX, IY
COMPLEX*16 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
END
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