triangle_witherden_rule


triangle_witherden_rule, a C++ code which returns a symmetric Witherden quadrature rule for the triangle, with exactness up to total degree 20.

The data is given for the following triangle:

      (0,1) 
        | \ 
        |  \ 
        |   \ 
        |    \ 
      (0,0)--(1,0)
      

We suppose we are given a triangle T with vertices A, B, C. We call a rule with n points, returning barycentric coordinates a, b, c, and weights w. Then the integral I of f(x,y) over T is approximated by Q as follows:

      (x,y) = a(1:n) * A + b(1:n) * B + c(1:n) * C
      Q = area(T) * sum ( 1 <= i <= n ) w(i) * f(x(i),y(i)) 
     

Licensing:

The computer code and data files made available on this web page are distributed under the MIT license

Languages:

triangle_witherden_rule is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave versionand a Python version.

Related Data and Programs:

triangle_witherden_rule_test

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Reference:

  1. Freddie Witherden, Peter Vincent,
    On the identification of symmetric quadrature rules for finite element methods,
    Computers and Mathematics with Applications,
    Volume 69, pages 1232-1241, 2015.

Source Code:


Last revised on 24 April 2023.