SUBROUTINE ACCEL(ISW,TFLO,ACC,IDM)
        COMMON IBUFF(255),DUMI(85),MANU,IBLK,CP,CV,CF
        COMMON/BLK1/VOLN(100),VOLX(100),FLON(110),FLOX(110),PRSN(100)
        COMMON/BLK2/ACCN(100),ACCX(100),PRSX(100)
        COMMON/BLK3/INEG,IPOS,IDIM,ITMP,IDIM1,IPAS,ISTOP,IREC
        COMMON/BLK4/HOLD(30),K,BUFF(1400),X,Y,APOS,J
	COMMON/BLK5/AMAT(5,5),COEF(4),COV(5,5),COR(5,5),A21(4)
	COMMON/BLK6/SD(5),A12(4),CEPT,DET,EPS,SX(5),SXY(5),SY,RATE
C		CALCULATES ACCELERATION AS 2ND OF SMOOTHED FLOW.
C		ISW=1 : ACCELERATION OF INSPIRATION
C		ISW=2 : ACCELERATION OF EXSPIRATION
	DIMENSION TFLO(1),ACC(1)
C		INITIALIZE DIFFERENTIATION PARAMETERS
C		.....................
  	STEP1=RATE/12.
	YY=TFLO(IDM-4)
	B=STEP1*(-25.*TFLO(1)+48.*TFLO(2)-36.*TFLO(3)+16.*TFLO(4)
     1		-3.*TFLO(5))
	C=STEP1*(-3.*TFLO(1)-10.*TFLO(2)+18.*TFLO(3)-
     1	6.*TFLO(4)+TFLO(5))
C		DIFFERENTIATION LOOP
	DO 30 I=5,IDM
	A=B
	B=C
	C=STEP1*(TFLO(I-4)-TFLO(I)+8.*(TFLO(I-1)-TFLO(I-3)))
	ACC(I-4)=A
  30	CONTINUE
	A=STEP1*(-YY+6.*TFLO(IDM-3)-18.*TFLO(IDM-2)+10.*TFLO(IDM-1)
     1		+3.*TFLO(IDM))
	ACC(IDM)=STEP1*(3.*YY-16.*TFLO(IDM-3)+36.*TFLO(IDM-2)
     1		-48.*TFLO(IDM-1)+25.*TFLO(IDM))
	ACC(IDM-1)=A
	ACC(IDM-2)=C
	ACC(IDM-3)=B
	RETURN
	END