quadrilateral_witherden_rule, a C code which returns a Witherden quadrature rule, with exactness up to total degree 21, over the interior of a quadrilateral.
The unit quadrilateral has vertices (0,0), (1,0), (1,1), (0,1).
The computer code and data files made available on this web page are distributed under the MIT license
quadrilateral_witherden_rule is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.
quadrilateral_witherden_rule_test