Pytrunc package

Pytrunc

A python package for the truncation of scattering phase functions in radiative transfer applications.

Provides

1. Analytic scattering phase functions: Henyey-Greenstein, two-term Henyey-Greenstein and Fournier-Forand

2. Phase function Legendre moments, computed numerically for an arbitrary phase function or analytically for the Henyey-Greenstein family

3. Truncation methods: the delta-m method and the Iwabuchi GT method

How to use the documentation

Documentation is available in two forms: docstrings provided with the code, and a standalone reference guide, available from the pytrunc homepage.

Code snippets are indicated by three greater-than signs:

>>> import numpy as np
>>> from pytrunc.phase import henyey_greenstein
>>> theta = np.linspace(0.0, 180.0, 1801)
>>> phase = henyey_greenstein(theta, g=0.85, normalize=2)

Use the built-in help function to view a function’s docstring:

>>> help(henyey_greenstein)

Modules

• pytrunc.truncation module
  • delta_m_phase_approx()
  • gt_phase_approx()
• pytrunc.phase module
  • calc_hg_moments()
  • calc_moments()
  • calc_tthg_moments()
  • fournier_forand()
  • henyey_greenstein()
  • two_term_henyey_greenstein()
• pytrunc.utils module
  • bessel_j1()
  • bessel_j1_derivative()
  • bessel_j1_roots()
  • bessel_jn()
  • integrate_lobatto()
  • legendre_polynomials()
  • legendre_polynomials_derivative()
  • legendre_polynomials_derivative_roots()
  • legendre_polynomials_second_derivative()
  • quadrature_lobatto()