How to Add a Species Constant (“Flag”)

Species constants are constants associated to all particles of a species. Hence they are included in the PIConGPU species type definition, located in the “Species Flags”.

Replace CONST with your new constant.

  1. add constant in lib/python/picongpu/pypicongpu/species/constant/CONST.py

    • inherit from Constant

  2. add test, checking at least for:

    • rendering from get_rendering_context()

    • check (even if check is empty)

    • typesafety

    • (possibly empty) dependencies on species, attributes, other constants

  3. (implement tests, add schema)

  4. add constant passthrough test in species test

    • add constant in map expected_const_by_name in test test_rendering_constants()

    • background: constants are not automatically exposed by the PyPIConGPU species class

  5. (implement test by adding passthrough from species.py)

  6. write PICMI test

    • new constant is created from PICMI

  7. (implement test)

  8. adjust code generation

    • keep in mind that your new constant is optional, i.e. use

      {{#constants.CONST}}
   my-code-to-generate-CONST = {{{value}}};
{{/constants.CONST}}

  9. create & compile an example

Note that constants are not stored in a list, but every constant type has a key in a dictionary associated to it. This means when adding a new constant the species class has to be adjusted to pass the new constant into its rendering context.