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SUBROUTINE ZSWAP(N,ZX,INCX,ZY,INCY)
* .. Scalar Arguments ..
INTEGER INCX,INCY,N
* ..
* .. Array Arguments ..
DOUBLE COMPLEX ZX(*),ZY(*)
* ..
*
* Purpose
* =======
*
* ZSWAP interchanges two vectors.
*
* Further Details
* ===============
*
* jack dongarra, 3/11/78.
* modified 12/3/93, array(1) declarations changed to array(*)
*
* =====================================================================
*
* .. Local Scalars ..
DOUBLE COMPLEX ZTEMP
INTEGER I,IX,IY
* ..
IF (N.LE.0) RETURN
IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
*
* code for both increments equal to 1
DO I = 1,N
ZTEMP = ZX(I)
ZX(I) = ZY(I)
ZY(I) = ZTEMP
END DO
ELSE
*
* 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 I = 1,N
ZTEMP = ZX(IX)
ZX(IX) = ZY(IY)
ZY(IY) = ZTEMP
IX = IX + INCX
IY = IY + INCY
END DO
END IF
RETURN
END
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