# LAMMPS Class

The LAMMPS class is encapsulating an MD simulation state and thus it is
the class that needs to be created when starting a new simulation system
state. The LAMMPS executable essentially creates one instance of this
class and passes the command line flags and tells it to process the
provided input (a file or `stdin`). It shuts the class down when control
is returned to it and then exits. When using LAMMPS as a library from
another code it is required to create an instance of this class, either
directly from C++ with `new LAMMPS()` or through one of the library
interface functions like `lammps_open`{.interpreted-text
role="cpp:func"} of the C-library interface, or the
`lammps.lammps`{.interpreted-text role="py:class"} class constructor of
the Python module, or the `lammps`{.interpreted-text role="f:func"}
constructor of the Fortran module.

In order to avoid clashes of function names, all of the core code in
LAMMPS is placed into the `LAMMPS_NS` namespace. Functions or variables
outside of that namespace must be \"static\", i.e. visible only to the
scope of the file/object they are defined in. Code in packages or the
libraries in the `lib` folder may not adhere to this as some of them are
adapted from legacy code or consist of external libraries with their own
requirements and policies.

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LAMMPS_NS::LAMMPS
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LAMMPS_NS::Pointers
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