TOMS886 a C++ code which implements an interpolation procedure based on "Padua points", defined in the square [-1,+1]^2, whose interpolating power is especially good. It is possible to map these points to the general rectangle, ellipse or triangle to do interpolation on these regions as well.
The text of many ACM TOMS algorithms is available online through ACM: http://calgo.acm.org/ or NETLIB: http://www.netlib.org/toms/index.html.
The computer code and data files made available on this web page are distributed under the GNU LGPL license.
TOMS886 is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version.
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Marco Caliari, Stefano de Marchi, Marco Vianello.