ADAS Subroutine xxpint

      subroutine xxpint(ndim, xa, ya, x, y)

C-----------------------------------------------------------------------
C
C  ******************** FORTRAN77 FUNCTION: XXPINT *********************
C
C  PURPOSE:  Order ndim polynominal interpolation.   
C
C  CALLING PROGRAM: adas408
C
C  FUNCTION:
C
C  input : (i*4)  ndim     = number of enteries in input arrays.
C  input : (r*8)  xa       = independent variable.
C  input : (r*8)  ya       = dependent variable.
C  input : (r*8)  x        = use requested x value.
C  output: (r*8)  y        = interpolated y value.
C
C  NOTES: Assume the starting value for y is ya(2).
C         Based on polint.for of Numerical Recipes.
C
C  ROUTINES:
C          ROUTINE    SOURCE    BRIEF DESCRIPTION
C          ------------------------------------------------------------
C          i4unit     ADAS      Fetch unit number for message output
C
C
C  VERSION  : 1.1                          
C  DATE     : 23-07-2003
C  MODIFIED : Martin O'Mullane
C              - First version.
C
C-----------------------------------------------------------------------
      INTEGER             NDIM
      REAL*8              X,           XA(NDIM),    Y
      REAL*8              YA(NDIM)