Cactus Code Thorn LocalInterp
Authors    : Jonathan Thornburg (jthorn@aei.mpg.de),
             incorporating parts of the old PUGHInterp by
             Thomas Radke (tradke@aei.mpg.de), which in turn draws
             on older code by Paul Walker and optimization ideas
             from Erik Schnetter (schnetter@uni-tuebingen.de)
CVS info   : $Header$
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Purpose of the thorn:

This thorn does processor-local interpolation of N-dimensional data
arrays.  In general there may be many input arrays (all defined on the
same uniform Cartesian grid) all being interpolated to the same set
of interpolation points.

This thorn actually packages together two separate local interpolators:
* One written by Thomas Radke in early 2001, with the operators
  "first order uniform cartesian", "second order uniform cartesian",
  and "third order uniform cartesian", all registered under the
  CCTK_InterpLocal() interpolation API.  (This formerly lived in
  the PUGHInterp thorn, but turned to have very little to do with
  PUGH, so it's been moved here.)  This lives in the subdirectory
  src/UniformCartesian/ .
* One written by Jonathan Thornburg in winter 2001-2002, with the
  operator "generalized polynomial interpolation" registered under
  the CCTK_InterpLocalUniform() interpolation API.  This lives in
  the subdirectory src/GeneralizedPolynomial-Uniform/ .

We plan to eventually phase out the CCTK_InterpLocal() API.  We may
also phase out its interpolator, or we may move this to the newer
CCTK_InterpLocalArrays() API.