SUBROUTINE SMOOTH( X, Y, N, ICOL, ISYM, ISIZE, INUM, LINTYP )
      LOGICAL STARTINEW, DRAWILINE, DRAWIMARK, INSIDE, INX0, INX
      LOGICAL VALID
      DIMENSION X(N), Y(N)
      COMMON /HSCALE/ XSLOPE, XCONST, YSLOPE, YCONST
      COMMON /WORLD/ XMIN, XMAX, YMIN, YMAX
      COMMON /CHKBON/ INSIDE, STARTINEW, LINNYP, LIN1, DASH
      DATA DYX / .5 /
      VALID = N .GE. 3
      IF(.NOT.( VALID )) GO TO 32759
      H0 = X(2) - X(1)
      DO 32758  I = 3, N
      H1 = X(I) - X(I-1)
      VALID = VALID .AND. ( H0 * H1 .GT. 0 )
32758 CONTINUE
32759 IF(.NOT.( VALID )) GO TO 32756
      DRAWILINE = INUM .GE. 0
      DRAWIMARK = ISIZE .GE. 1 .AND. ISIZE .LE. 5
      DRAWIMARK = DRAWIMARK .AND. ISYM .GE. 0 .AND. ISYM .LE. 5
      DRAWIMARK = DRAWIMARK .AND. INUM .NE. 0
      IF(.NOT.( DRAWILINE )) GO TO 32755
      STARTINEW = .TRUE.
      CALL COLTYP(ICOL)
      OPEN( UNIT=1, TYPE='SCRATCH' )
      DO 32754  I = 1, N
      WRITE(1,*) X(I), Y(I)
32754 CONTINUE
      REWIND 1
      H0 = X(2) - X(1)
      Y0 = 6 * ( Y(2) - Y(1) ) / H0
      FAC = 0.
      DO 32753  I = 2, N-1
      H1 = X(I+1) - X(I)
      X(I) = ( 2 * ( H1 + H0 ) - FAC ) / H1
      Y1 = 6 * ( Y(I+1) - Y(I) ) / H1
      Y(I) = ( Y1 - Y0 - Y(I-1) * FAC ) / H1
      Y0 = Y1
      H0 = H1
      FAC = H0 / X(I)
32753 CONTINUE
      Y(1) = 0.
      Y(N) = 0.
      DO 32752  I = N-1, 2, -1
      Y(I) = ( Y(I) - Y(I+1) ) / X(I)
32752 CONTINUE
      C0 = Y(1)
      READ(1,*) X(1), Y(1)
      CALL MOVETO( X(1), Y(1), 0, LINTYP )
      INX0 = ( X(1) - XMIN ) * ( XMAX - X(1) ) .GE. 0.
      DO 32751  I = 2, N
      C1 = Y(I)
      READ(1,*) X(I), Y(I)
      INX = ( X(I) - XMIN ) * ( XMAX - X(I) ) .GE. 0.
      H = X(I) - X(I-1)
      B = Y(I) / H - C1 * H / 6.
      D = Y(I-1) / H - C0 * H / 6.
      SQR = SQRT( ( C0 * C0 + C1 * C1 + C0 * C1 ) * 3. )
      ANUM = C1 + 2 * C0
      ADEN = 3 * C0 + SQR
      DY = 0.
      DC = C1 - C0
      IF(.NOT.( ANUM*ADEN .GT. 0. .AND. ANUM*ADEN .LT. ADEN*ADEN )) GO T
     1O 32750
      DX = ANUM / ADEN
      DY = ABS( DX * (( DC * DX + 3 * C0 ) * DX - ANUM ) )
32750 ADEN = 3 * C0 - SQR
      IF(.NOT.( ANUM*ADEN .GT. 0. .AND. ANUM*ADEN .LT. ADEN*ADEN )) GO T
     1O 32749
      DX = ANUM / ADEN
      DY1 = ABS( DX * (( DC * DX + 3 * C0 ) * DX - ANUM ) )
      DY = AMAX1( DY, DY1 )
32749 DY = ABS( YSLOPE * H * H * DY / 6. )
      IF(.NOT.( DY .GE. DYX .AND. ( INX0 .OR. INX ) )) GO TO 32748
      NN = DY / DYX + 1
      DO 32747  J = 1, NN - 1
      XI0 = ( H * J ) / NN
      XI = XI0 + X(I-1)
      XI1 = H - XI0
      YI = XI0 * ( C1 * XI0 * XI0 / ( 6 * H ) + B )
      YI = YI + XI1 * ( C0 * XI1 * XI1 / ( 6 * H ) + D )
      CALL MOVETO( XI, YI, 1, LINTYP )
32747 CONTINUE
32748 INX0 = INX
      C0 = C1
      CALL MOVETO( X(I), Y(I), 1, LINTYP )
32751 CONTINUE
      CLOSE ( UNIT=1 )
32755 IF(.NOT.( DRAWIMARK )) GO TO 32746
      STARTINEW = .TRUE.
      ITEMP = IABS(INUM)
      CALL COLTYP(ICOL)
      DO 32745  I = 1, N, ITEMP
      CALL MOVETO( X(I), Y(I), 0, LINTYP )
      IF ( INSIDE ) CALL MARKER( ISYM, ISIZE )
32745 CONTINUE
32746 GO TO 32757
32756 CALL DASHLN( X, Y, N, ICOL, ISYM, ISIZE, INUM, LINTYP )
32757 RETURN
      END