Describe and run systems diagrams.
`systems` is a set of tools for describing, running and visualizing
Installation directions are below, and then get started by [working through the tutorial](./docs/tutorial.md)
or reading through the [Jupyter notebook example](../notebooks/hiring.ipynb) example.
For a more in-depth look at the system syntax, please read [the syntax specification](./docs/spec.md).
## Quickest start
Follow the installation instructions below, then write a system definition
Start > Middle @ 2
Middle > End
You can then evaluate your system (use `--csv` for an importable format):
cat tmp.txt | systems-run -r 3
Start Middle End
0 10 0 0
1 8 2 0
2 6 3 1
3 4 4 2
See [the tutorial](./docs/tutorial.md) for more detailed starting information.
## Jupyter notebooks
Likely the easiest way to iterate on a model is within a Jupyter notebook.
See an [example notebook here](./notebooks/hiring.ipynb).
[Read this blog post for more installation details](https://lethain.com/systems-jupyter-notebook/).
To install via PyPi:
pip install systems
To install for local development:
git clone https://github.com/lethain/systems.git
python3 -m venv ./env
python setup.py develop
Run tests via:
python3 -m unittest tests/test_*.py
Or run a single test via:
python3 tests/test_parse.py TestParse.test_parse_complex_formula
Please open an Github issue if you run into any problems!
## Using the command line tools
There are four command line tools that you'll use when creating and debugging
`systems-run` is used to run models:
$ cat examples/hiring.txt | systems-run -r 3
PhoneScreens Onsites Offers Hires Employees Departures
0 0 0 0 0 5 0
1 25 0 0 0 5 0
2 25 12 0 0 5 0
3 25 12 6 0 5 0
`systems-viz` is used to visualize models into [Graphviz](https://www.graphviz.org/):
$ cat examples/hiring.txt | systems-viz
// etc, etc, some other stuff
Typically you'll pipe the output of `systems-viz` into `dot`, for example
$ cat examples/hiring.txt | systems-viz | dot -Tpng -o tmp.png
`systems-format` reads in a model, tokenizes it and formats the tokens
into properly formatted results. This is similar to `gofmt`, and could
be used for ensuring a consistent house formatting style for your diagrams.
(It was primarily implemented to support generating human readable error
messages instead of surfacing the tokens to humans when errors arise.)
$ cat examples/hiring.txt | systems-fmt
[Candidates] > PhoneScreens @ 25
PhoneScreens > Onsites @ 0.5
# etc etc
`systems-lex` generates the tokens for a given system file.
This is typically most useful when you're extending the lexer
to support new types of functionality, but can also be useful
for other kinds of debugging:
$ cat examples/hiring.txt | systems-lex
[('comment', '# wrap with  to indicate an infinite stock that')]),
('line', 2, [('comment', "# isn't included in each table")]),
('line', 3, [('comment', '# integers are implicitly steady rates')]),
[('infinite_stock', 'Candidates', ('params', )),
('stock', 'PhoneScreens', ('params', ())),
('flow', '', ('params', (('formula', [('whole', '25')]),)))]),
## Error messages
The parser will do its best to give you a useful error message.
For example, if you're missing delimiters:
cat examples/no_delim.txt | systems-run
line 1 is missing delimiter '>': "[a] < b @ 25"
At worst, it will give you the line number and line that is
creating an issue:
cat examples/invalid_flow.txt | systems-run
line 1 could not be parsed: "a > b @ 0..2"
## Uploading distribution
If you are trying to install this on PyPi, the steps are roughly:
python3 -m pip install --user --upgrade pip
python3 -m pip install --user --upgrade wheel
python3 -m pip install --user --upgrade twine
python3 setup.py sdist bdist_wheel
twine upload --repository-url https://upload.pypi.org/legacy/ dist/*
That should more or less work. :)
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