IntExpR:

--------------------------------------------------------------------------
   One dimensional interpolation and extrapolation on the rows of a.
--------------------------------------------------------------------------
   Form:
   c = IntExpR( a, x, xC )
--------------------------------------------------------------------------

   ------
   Inputs
   ------
   a                      Two dimensional matrix
   x                      Column values
   xC                     Points at which a is to be computed

   -------
   Outputs
   -------
   c                      Extrapolated/interpolated values

--------------------------------------------------------------------------