SUBROUTINE CSWAP(N,CX,INCX,CY,INCY) * .. Scalar Arguments .. INTEGER INCX,INCY,N * .. * .. Array Arguments .. COMPLEX CX(*),CY(*) * .. * * Purpose * ======= * * interchanges two vectors. * jack dongarra, linpack, 3/11/78. * modified 12/3/93, array(1) declarations changed to array(*) * * * .. Local Scalars .. COMPLEX CTEMP INTEGER I,IX,IY * .. 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 = CX(IX) CX(IX) = CY(IY) CY(IY) = CTEMP IX = IX + INCX IY = IY + INCY 10 CONTINUE RETURN * * code for both increments equal to 1 20 DO 30 I = 1,N CTEMP = CX(I) CX(I) = CY(I) CY(I) = CTEMP 30 CONTINUE RETURN END