PROGRAM CUBGCVMAIN
	   USE MODCUBGCV
C CUBGCV TEST DRIVER
C ------------------
C
C AUTHOR          - M.F.HUTCHINSON
C                   CSIRO DIVISION OF WATER AND LAND RESOURCES
C                   GPO BOX 1666
C                   CANBERRA ACT 2601
C                   AUSTRALIA
C
C LATEST REVISION - 7 AUGUST 1986
C
C COMPUTER        - VAX/DOUBLE
C
C USAGE           - MAIN PROGRAM
C
C REQUIRED ROUTINES - CUBGCV,SPINT1,SPFIT1,SPCOF1,SPERR1,GGRAND
C
C REMARKS   USES SUBROUTINE CUBGCV TO FIT A CUBIC SMOOTHING SPLINE
C           TO 50 DATA POINTS WHICH ARE GENERATED BY ADDING A RANDOM
C           VARIABLE WITH UNIFORM DENSITY IN THE INTERVAL [-0.3,0.3]
C           TO 50 POINTS SAMPLED FROM THE CURVE  Y=SIN(3*PI*X/2).
C           RANDOM DEVIATES IN THE INTERVAL [0,1] ARE GENERATED BY THE
C           DOUBLE PRECISION FUNCTION GGRAND (SIMILAR TO IMSL FUNCTION
C           GGUBFS).  THE ABSCISSAE ARE UNEQUALLY SPACED IN [0,1].
C
C           POINT STANDARD ERROR ESTIMATES ARE RETURNED IN SE BY
C           SETTING JOB=1.  THE ERROR VARIANCE ESTIMATE IS RETURNED
C           IN VAR.  IT COMPARES FAVOURABLY WITH THE TRUE VALUE OF 0.03.
C           SUMMARY STATISTICS FROM THE ARRAY WK ARE WRITTEN TO
C           UNIT 6.  DATA VALUES AND FITTED VALUES WITH ESTIMATED
C           STANDARD ERRORS ARE ALSO WRITTEN TO UNIT 6.
C
      PARAMETER (N=50, IC=49)
C
      INTEGER            JOB,IER
      DOUBLE PRECISION   X(N),F(N),Y(N),DF(N),C(IC,3),WK(7*(N+2)),
     *                   VAR,SE(N)
      DOUBLE PRECISION   GGRAND,DSEED
C
C---INITIALIZE---
      DSEED=1.2345D4
      JOB=1
      VAR=-1.0D0
C
C---CALCULATE DATA POINTS---
      DO 10 I=1,N
      X(I)=(I - 0.5)/N + (2.0*GGRAND(DSEED) - 1.0)/(3.0*N)
      F(I)=DSIN(4.71238*X(I)) + (2.0*GGRAND(DSEED) - 1.0)*0.3
      DF(I)=1.0D0
  10  CONTINUE
C
C---FIT CUBIC SPLINE---
      CALL CUBGCV(X,F,DF,N,Y,C,IC,VAR,JOB,SE,WK,IER)
C
C---WRITE OUT RESULTS---
      WRITE(6,20)
  20  FORMAT(' CUBGCV TEST DRIVER RESULTS:')
      WRITE(6,30) IER,VAR,WK(3),WK(4),WK(2)
  30  FORMAT(/' IER =',I4/' VAR =',F7.4/
     *        ' GENERALIZED CROSS VALIDATION =',F7.4/
     *        ' MEAN SQUARE RESIDUAL         =',F7.4/
     *        ' RESIDUAL DEGREES OF FREEDOM  =',F7.2)
      WRITE(6,40)
  40  FORMAT(/' INPUT DATA',17X,'OUTPUT RESULTS'//
     *         '   I    X(I)    F(I)',6X,'    Y(I)   SE(I)',
     *          '      C(I,1)      C(I,2)      C(I,3)')
      DO 60 I=1,N-1
      WRITE(6,50) I,X(I),F(I),Y(I),SE(I),(C(I,J),J=1,3)
  50  FORMAT(I4,2F8.4,6X,2F8.4,3E12.4)
  60  CONTINUE
      WRITE(6,50) N,X(N),F(N),Y(N),SE(N)
      STOP
      END
      DOUBLE PRECISION FUNCTION GGRAND(DSEED)
C
C DOUBLE PRECISION UNIFORM RANDOM NUMBER GENERATOR
C
C CONSTANTS: A = 7**5
C            B = 2**31 - 1
C            C = 2**31
C
C REFERENCE: IMSL MANUAL, CHAPTER G - GENERATION AND TESTING OF
C                                     RANDOM NUMBERS
C
C---SPECIFICATIONS FOR ARGUMENTS---
      DOUBLE PRECISION DSEED
C
C---SPECIFICATIONS FOR LOCAL VARIABLES---
      DOUBLE PRECISION A,B,C,S
C
      DATA A,B,C/16807.0D0, 2147483647.0D0, 2147483648.0D0/
C
      S=DSEED
      S=DMOD(A*S, B)
      GGRAND=S/C
      DSEED=S
      RETURN
      END