ADAS Subroutine lfasym

       SUBROUTINE LFASYM(X,XA,N,YA,Y,DY,C1,C2,C3,C4,FORM,IFORMS)
       IMPLICIT REAL*8(A-H,O-Z)
C-----------------------------------------------------------------------
C                                                                       
C  ************  FORTRAN 77 SUBROUTINE: LFASYM *************************
C                                                                       
C  PURPOSE: TO PROVIDE A SPLINE INTERPOLATE MAKING USE OF SPECIFIED
C  ASYMPTOTIC BEHAVIOUR
C
C  LARGER ARRAY DIMENSION VERSION OF NFASYM
C
C  USES LABELLED COMMON /LSPL3/
C
C  INPUT
C      X=REQUIRED X-VALUE
C      X(I)=KNOTS
C      N=NUMBER OF KNOTS
C      C1(I,J)=1ST SPINE COEFFICIENT PRECURSOR
C      C2(I,J)=2ND SPINE COEFFICIENT PRECURSOR
C      C3(I,J)=3RD SPINE COEFFICIENT PRECURSOR
C      C4(I,J)=4TH SPINE COEFFICIENT PRECURSOR
C      FORM=EXTERNAL FUNCTION SPECIFYING ASYMPTOTIC FORMS
C      IFORMS=INDEX OF REQUIRED FORM
C  OUTPUT
C      Y=RETURNED Y-VALUE
C      DY=RETURNED DERIVATIVE
C
C AUTHOR:
C
C  ********** H.P. SUMMERS, JET             7 FEB 1989   ***********
C-----------------------------------------------------------------------
C
C UNIX-IDL CONVERSION:
C
C VERSION: 1.1                          DATE: 07-10-96
C MODIFIED: WILLIAM OSBORN
C               - FIRST CONVERTED.
C
C VERSION: 1.2                          DATE: 15-05-07
C MODIFIED: Allan Whiteford
C               - Updated comments as part of subroutine
C                 documentation production.
C
C----------------------------------------------------------------------
      INTEGER             IFORMS,      N
      REAL*8              C1(40,39),   C2(40,39),   C3(40,39)
      REAL*8              C4(40,39),   DY,          X,           XA(40)
      REAL*8              Y,           YA(40)