SUBROUTINE DROT(N,DX,INCX,DY,INCY,C,S)
DOUBLE PRECISION C,S
INTEGER INCX,INCY,N
DOUBLE PRECISION DX(*),DY(*)
DOUBLE PRECISION DTEMP
INTEGER I,IX,IY
IF (N.LE.0) RETURN
IF (INCX.EQ.1 .AND. INCY.EQ.1) GO TO 20
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
DTEMP = C*DX(IX) + S*DY(IY)
DY(IY) = C*DY(IY) - S*DX(IX)
DX(IX) = DTEMP
IX = IX + INCX
IY = IY + INCY
10 CONTINUE
RETURN
20 DO 30 I = 1,N
DTEMP = C*DX(I) + S*DY(I)
DY(I) = C*DY(I) - S*DX(I)
DX(I) = DTEMP
30 CONTINUE
RETURN
END