# Dump styles

Classes that dump per-atom info to files are derived from the Dump
class. To dump new quantities or in a new format, a new derived dump
class can be added, but it is typically simpler to modify the DumpCustom
class contained in the dump_custom.cpp file.

Dump_atom.cpp is a simple example of a derived dump class.

Here is a brief description of methods you define in your new derived
class. See dump.h for details.

  --------------- ---------------------------------------------------
  write_header    write the header section of a snapshot of atoms

  count           count the number of lines a processor will output

  pack            pack a proc\'s output data into a buffer

  write_data      write a proc\'s data to a file
  --------------- ---------------------------------------------------

See the [dump](dump) command and its *custom* style for a list of
keywords for atom information that can already be dumped by DumpCustom.
It includes options to dump per-atom info from Compute classes, so
adding a new derived Compute class is one way to calculate new
quantities to dump.

Note that new keywords for atom properties are not typically added to
the [dump custom](dump) command. Instead they are added to the [compute
property/atom](compute_property_atom) command.