Graphtik¶

(src: 6.1.0, git: v6.0.0-9-ga14d616 , Apr 14, 2020)

It’s a DAG all the way down!

Lightweight computation graphs for Python¶

Graphtik is an an understandable and lightweight Python module for building and running ordered graphs of computations. The API posits a fair compromise between features and complexity, without precluding any. It can be used as is to build machine learning pipelines for data science projects. It should be extendable to act as the core for a custom ETL engine or a workflow-processor for interdependent files and processes.

Graphtik sprang from Graphkit to experiment with Python 3.6+ features.

Quick start¶

Here’s how to install:

pip install graphtik

OR with dependencies for plotting support (and you need to install Graphviz program separately with your OS tools):

pip install graphtik[plot]

Let’s build a graphtik computation graph that produces x3 outputs out of 2 inputs a and b:

\[ \begin{align}\begin{aligned}a \times b\\a - a \times b\\|a - a \times b| ^ 3\end{aligned}\end{align} \]

>>> from graphtik import compose, operation
>>> from operator import mul, sub

>>> @operation(name="abs qubed",
...            needs=["a_minus_ab"],
...            provides=["abs_a_minus_ab_cubed"])
... def abs_qubed(a):
...    return abs(a) ** 3

Compose the abspow function along with mul & sub built-ins into a computation graph:

>>> graphop = compose("graphop",
...    operation(needs=["a", "b"], provides=["ab"])(mul),
...    operation(sub, needs=["a", "ab"], provides=["a_minus_ab"])(),
...    abs_qubed,
... )
>>> graphop
NetworkOperation('graphop', needs=['a', 'b', 'ab', 'a_minus_ab'],
                  provides=['ab', 'a_minus_ab', 'abs_a_minus_ab_cubed'],
                  x3 ops: <built-in function mul>, <built-in function sub>, abs qubed)

You may plot the function graph in a file like this (if in jupyter, no need to specify the file, see Jupyter notebooks):

>>> graphop.plot('graphop.svg')      # doctest: +SKIP

As you can see, any function can be used as an operation in Graphtik, even ones imported from system modules.

Run the graph-operation and request all of the outputs:

>>> sol = graphop(**{'a': 2, 'b': 5})
>>> sol
{'a': 2, 'b': 5, 'ab': 10, 'a_minus_ab': -8, 'abs_a_minus_ab_cubed': 512}

Run the graph-operation and request a subset of the outputs:

>>> solution = graphop.compute({'a': 2, 'b': 5}, outputs=["a_minus_ab"])
>>> solution
{'a_minus_ab': -8}

Solutions are plottable as well:

>>> solution.plot('solution.svg')      # doctest: +SKIP

… where the (interactive) legend is this:

>>> from graphtik.plot import legend
>>> l = legend()