SUBROUTINE XVPRED(I1,NNB)
*
*
*       Prediction of coordinates & velocities.
*       ---------------------------------------
*
      INCLUDE 'common6.h'
*
*
*       Perform full N prediction to highest order (defined by NNB >= N).
      IF (NNB.GE.N) GO TO 20
*       Use high order for special singles (NNB < 0) or c.m. bodies (I1 > N).
      IF (NNB.LT.0.OR.(NNB.EQ.0.AND.I1.GT.N)) GO TO 20
*
*       Adopt low order for standard single particles (I1 <= N & NNB = 0).
      IF (NNB.EQ.0) THEN
          I = I1
          S = TIME - T0(I)
          IF (S.EQ.0.0D0) GO TO 40
          S1 = 1.5*S
          S2 = 2.0*S
          X(1,I) = ((FDOT(1,I)*S + F(1,I))*S + X0DOT(1,I))*S + X0(1,I)
          X(2,I) = ((FDOT(2,I)*S + F(2,I))*S + X0DOT(2,I))*S + X0(2,I)
          X(3,I) = ((FDOT(3,I)*S + F(3,I))*S + X0DOT(3,I))*S + X0(3,I)
          XDOT(1,I) = (FDOT(1,I)*S1 + F(1,I))*S2 + X0DOT(1,I)
          XDOT(2,I) = (FDOT(2,I)*S1 + F(2,I))*S2 + X0DOT(2,I)
          XDOT(3,I) = (FDOT(3,I)*S1 + F(3,I))*S2 + X0DOT(3,I)
          GO TO 40
      END IF
*
*       Predict all neighbours to order FDOT.
      NNB1 = NNB + 1
      DO 5 L = 2,NNB1
          I = LIST(L,I1)
          S = TIME - T0(I)
          IF (S.EQ.0.0D0) GO TO 5
          S1 = 1.5*S
          S2 = 2.0*S
          X(1,I) = ((FDOT(1,I)*S + F(1,I))*S + X0DOT(1,I))*S + X0(1,I)
          X(2,I) = ((FDOT(2,I)*S + F(2,I))*S + X0DOT(2,I))*S + X0(2,I)
          X(3,I) = ((FDOT(3,I)*S + F(3,I))*S + X0DOT(3,I))*S + X0(3,I)
          XDOT(1,I) = (FDOT(1,I)*S1 + F(1,I))*S2 + X0DOT(1,I)
          XDOT(2,I) = (FDOT(2,I)*S1 + F(2,I))*S2 + X0DOT(2,I)
          XDOT(3,I) = (FDOT(3,I)*S1 + F(3,I))*S2 + X0DOT(3,I)
    5 CONTINUE
*
*       Resolve the components of any perturbed pairs (last neighbours).
   10 I = LIST(NNB1,I1)
      IF (I.GT.N) THEN
          JPAIR = I - N
          IF (LIST(1,2*JPAIR-1).GT.0) THEN
              CALL RESOLV(JPAIR,1)
          END IF
          NNB1 = NNB1 - 1
          IF (NNB1.GT.1) GO TO 10
      END IF
      GO TO 40
*
*       Set index of first body (#I1 if NNB = 0 or NNB >= N).
   20 I = I1
*       Predict coordinates & velocities of body #I to order F3DOT.
   25 DT = TIME - T0(I)
      IF ((DT.EQ.0.0D0.AND.IPHASE.LT.4).OR.BODY(I).EQ.0.0D0) GO TO 35
      A1 = 0.05*DT
      A2 = 0.25*DT
      A3 = T0(I) - T0R(I)
      A4 = 0.5*A3
*
      DO 30 K = 1,3
          FK = ((ONE6*D3R(K,I)*A3 + 0.5*D2R(K,I))*A3 + D1R(K,I))*A3
     &                                              + D0R(K,I) + D0(K,I)
          F1DOTK = (D3R(K,I)*A4 + D2R(K,I))*A3 + D1R(K,I) + D1(K,I)
          F2DOTK = 0.5*(D3R(K,I)*A3 + D2R(K,I) + D2(K,I))
          F3DOTK = ONE6*(D3R(K,I) + D3(K,I))
          X(K,I) = ((((F3DOTK*A1 + ONE12*F2DOTK)*DT +
     &                   ONE6*F1DOTK)*DT + 0.5*FK)*DT + X0DOT(K,I))*DT +
     &                   X0(K,I)
          XDOT(K,I)  = (((F3DOTK*A2 + ONE3*F2DOTK)*DT +
     &                            0.5*F1DOTK)*DT + FK)*DT + X0DOT(K,I)
   30 CONTINUE
*
*       Resolve the components of perturbed pairs.
   35 IF (I.GT.N) THEN
          JPAIR = I - N
          IF (LIST(1,2*JPAIR-1).GT.0) THEN
              CALL RESOLV(JPAIR,1)
          END IF
      END IF
*
*       Check whether prediction of single particle or full N.
      IF (NNB.GT.0) THEN
          I = I + 1
          IF (I.LE.NNB) GO TO 25
      END IF
*
   40 RETURN
*
      END