Metadata-Version: 2.1
Name: bondgraph
Version: 0.1.1
Summary: A library to create bond graphs for physical systems and generate their differential equations.
Author-email: Karl Linderhed <bondgraph@karlinde.se>
License: MIT License
        
        Copyright (c) 2022 Karl Linderhed
        
        Permission is hereby granted, free of charge, to any person obtaining a copy
        of this software and associated documentation files (the "Software"), to deal
        in the Software without restriction, including without limitation the rights
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        copies of the Software, and to permit persons to whom the Software is
        furnished to do so, subject to the following conditions:
        
        The above copyright notice and this permission notice shall be included in all
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        THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
        IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
        FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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        SOFTWARE.
        
Project-URL: repository, https://github.com/karlinde/bondgraph
Project-URL: Bug Tracker, https://github.com/karlinde/bondgraph/issues
Classifier: Programming Language :: Python :: 3
Classifier: License :: OSI Approved :: MIT License
Classifier: Operating System :: OS Independent
Requires-Python: >=3.10
Description-Content-Type: text/markdown
Provides-Extra: visualization
License-File: LICENSE

# bondgraph
[![Python package](https://github.com/Karlinde/bondgraph/actions/workflows/python-package.yaml/badge.svg)](https://github.com/Karlinde/bondgraph/actions/workflows/python-package.yaml)

A python library for creating [bond graphs](https://en.wikipedia.org/wiki/Bond_graph) of 
physical systems and generating differential equations.

It heavily relies on `sympy` for manipulation and simplification of equations symbolically.

## Installation
Install via pip:
```
pip install bondgraph
```

To install with extra dependencies for visualization using graphviz:
```
pip install bondgraph[visualization]
``` 

## Usage
Create a `BondGraph` object and add `Bond` objects connecting various elements:
```python
# This example generates the following simple bond graph:
#
# Se ---> 1 ---> I
#         |
#         v
#         R

from bondgraph.core import Bond, BondGraph
from bondgraph.junctions import JunctionEqualFlow
from bondgraph.elements.basic import Element_R, Element_I, Source_effort
from sympy import Symbol

force = Source_effort("force", Symbol("F"))
friction = Element_R("friction", Symbol("k_f"))
inertia = Element_I("inertia", Symbol("m"), Symbol("p"))
mass_object = JunctionEqualFlow("mass_object")

graph = BondGraph()
graph.add(Bond(force, mass_object))
graph.add(Bond(mass_object, friction))
graph.add(Bond(mass_object, inertia))

state_equations = graph.get_state_equations()

# Print the dictionary of state variables and the right hand side of their state equations:
print(state_equations)
# {p: F - k_f*p/m}

# If using the optional visualization features, generate and display a graphviz graph:
from bondgraph.visualization import gen_graphviz

output_graph = gen_graphviz(graph)
output.view()
```

## Limitations
- Algebraic loops are not handled at all and will result in failure to generate equations.
- Non-integrating (differential) causality for C or I elements is not currently possible.

