Basic conventions

PTS is written for Python 3.7 or later and, in general, uses the coding style, language capabilities and standard library functions corresponding to that language version.

As an important exception to this rule, the comment blocks preceding classes and functions in the code use the # style as opposed to the more pythonic doc-string style. The main reason is that older versions of Doxygen (see Generating the SKIRT project documentation) did not recognize the special commands for LaTeX formulas and extra formatting in doc strings.

The following table summarizes the PTS naming conventions used for Python language entities:

Entity	Convention	Example
Package (directory)	All lowercase letters, no separators	storedtable
Module (file)	All lowercase letters, no separators	skirtsimulation
Class	Camel case starting with upper case letter	SkiFile
Function	Camel case starting with lower case letter	performSimulation()
-> getter	name of property	backgroundColor()
-> setter	set + capitalized name of property	setBackgroundColor()
Variable	Camel case starting with lower case letter; or all lowercase letters, no separators	nx, fluxDensity
Data member	Leading underscore plus variable name (all data members are private)	_nx, _fluxDensity

Organizing package functionality

Each PTS package (a directory, see Overall structure of the PTS code) exposes all public functions and classes (i.e. those intended for use outside of the package) at the package level. The functionality is implemented in various modules (python source files) residing inside the package. The initialization file for each package places the public names into the package namespace using explicit imports.

Importing packages

Default style for importing external packages (including standard-library packages):

import os.path
import pathlib

External packages imported with a local name:

import astropy.constants as const
import astropy.io.fits as fits
import astropy.units as u
import lxml.etree as etree
import matplotlib.pyplot as plt
import numpy as np

Importing other PTS packages (or same package from within do subdirectory):

import pts.admin as adm
import pts.band as bnd
import pts.do as do
import pts.simulation as sm
import pts.storedtable as stab
import pts.utils as ut
import pts.visual as vis

Importing symbols from within the same package, including initialization file:

from .module import name      # default style is to use explicit import
from .module import *         # exceptional style, for example in conversionspec.py

External dependencies

Any PTS code may depend on any of the standard Python 3.7 packages without further mention. In addition, some of the PTS facilities may require non-standard Python packages to be installed. Developers are urged to avoid additional dependencies where possible, and to use only packages that are readily available from the common distribution channels.

Refer to the required non-standard packages for a list at the time of writing. To obtain a list of the current package dependencies, make sure that PTS is properly installed and enter the following terminal command:

pts list_dependencies