The source code of the quadraturerules Fortran 90 library can be downloaded from the latest release on GitHub.
The library's tests can be built by running:
gfortran test.f90 -o test
./test
The library's function single_integral_quadrature can be used to get the points and weights of quadrature rules. For example the following snippet will create an order 3 Xiao–Gimbutas rule on a triangle:
use quadraturerules
real, allocatable :: points(:,:), weights(:)
call single_integral_quadrature(QR_GaussLegendre, QR_Interval, 5, points, weights)
Note that the points returned by the library are represented using barycentric coordinates.
The Fortran 90 quadraturerules library can be generated from the templates in the online encyclopedia of quadrature rules GitHub repo. First clone the repo and move into the library directory:
git clone https://github.com/quadraturerules/quadraturerules.git
cd quadraturerules/library
The Fortran 90 library can then be generated by running:
python build.py fortran90
This will create a directory called fortran90.build containing the Fortran 90 source code.