9. Core modules

The MDAnalysis.core modules contain functionality essential for MDAnalysis, such as the central data structures in MDAnalysis.core.universe and MDAnalysis.core.groups or the selection definitions and parsing in MDAnalysis.core.selection.

9.1. Important objects for users

All users of MDAnalysis need to understand the two most important classes in this section, namely the Universe and the AtomGroup.

9.3. Selection system

The selection system is primarily of interest to developers.

9.4. Flag system

The flag system contains the global behavior of MDAnalysis. It is normally not necessary to change anything here.