Design Notes

This section describes miscellaneous information about the design of payu.

Model and Experiment Layout

Laboratory Structure

An experiment requires that the model executable, configuration, and data files be staged in the appropriate directories, outlined below:

Control Path
Configuration files are stored here, and is also the directory where payu is invoked. This is usually the current working directory.
Laboratory Path
This is the top-level directory for a particular model, and contains the model executables, input data, and model output for all experiments using this model. The default directory is /short/${PROJECT}/${USER}/${MODEL}.

Herein, ${LAB} refers to the laboratory path.

Executable Path
Model executables are stored here. The default is ${LAB}/bin.
Input Path
Data files are stored here. The default is ${LAB}/input.
Codebase Path (not currently supported)
The sourcecode of the current active executable will be stored in this directory. The default is ${LAB}/codebase.
Archive Path
Model output is stored in this directory, separated by experiment. For an experiment named myrun, the archived output is stored in ${LAB}/archive/myrun/output000, output001, output002, etc. and restart information is stored in restart000, restart001, etc.
Work Path
Experiments that are actively running are stored in the work path. For an experiment named myrun, the default directory is ${LAB}/work/myrun.

Style Guide

These are various unorganised notes on preferred coding style for payu. While it’s unlikely that every file adheres to this style, it should generally be adopted where possible.

  1. All files should adhere to PEP8 rules. In particular, no warnings should be reported by pycodestyle using default settings.

  2. Docstrings should similarly adhere to PEP257, as reported by pydocstyle. (Currently conformance to this rule is admittedly very poor.)

    In particular, help() should be readable and well-formatted for every module and function.

  3. Modules should not be renamed. This is bad:

    ``import numpy as np``

    This is good:

    ``import numpy``

    The reason here is to preserve shorter names for other uses in the code. But, as usual, the HHGP’s section on modules explains this better than I can within a bullet point list.

    (Also note that this is another rule with poor conformance.)

  4. Multiple equivalence checks should use tuples. This is bad:

    if x == 'a' or x == 'b'

    This is good:

    if x in ('a', 'b')