2.3.1. Introduction to Angular Quadratures

Discrete-ordinates calculations use an angular quadrature to select sweep directions, associate a weight with each direction, and transform between angular fluxes and flux moments. These shared properties and operators are exposed by AngularQuadrature.

The pyopensn.aquad module provides the following concrete quadratures:

• GLProductQuadrature1DSlab is a Gauss-Legendre product rule for one-dimensional slab geometry.

• GLCProductQuadrature2DXY and GLCProductQuadrature3DXYZ combine Gauss-Legendre polar points with Gauss-Chebyshev azimuthal points for Cartesian geometry.

• GLCProductQuadrature2DRZ provides the corresponding product rule for two-dimensional cylindrical geometry.

• GLCTriangularQuadrature2DXY and GLCTriangularQuadrature3DXYZ decrease the azimuthal order toward the poles to form triangular quadrature sets.

• SLDFEsqQuadrature2DXY and SLDFEsqQuadrature3DXYZ use square linear-discontinuous finite elements and support local refinement in angle.

• LebedevQuadrature2DXY and LebedevQuadrature3DXYZ use Lebedev point sets.

Each constructor accepts an operator_method selecting how the discrete-to-moment and moment-to-discrete maps are built. The available values are "standard", "galerkin_one", and "galerkin_three".

See the Python API reference for quadrature orders, scattering-order requirements, and the data and operators available on each class.