Multifunctional

Handling multifunctional activities in the Brightway LCA software framework.

Multifunctional activities can lead to linear algebra problems which don't have exactly one solution. Therefore, we commonly need to apply a handling function to either partition such activities, or otherwise manipulate their data such that they allow for the creation of a non-singular, square technosphere matrix.

This library is designed around the following workflow:

1. Multifunctional activities are created and saved in their original form, with multiple functional flows. These flows can be either outputs (e.g. products) or input (e.g. waste treatment). Functional exchanges are either manually or automatically labeled as such: exchange_instance['functional'] = True.
2. Saving a functional flow will automatically create a new product node in the supply chain graph.
3. Multifunctional activities must be given a handler function label: activity_instance['handler'] = 'some_handler_function_label'. Handler function labels are strings.
4. Handler functions are mapped in multifuntional.handler_mapping. This library provides a default set of handling functions (see below); users may also add custom handlers.
5. When the database is processed, the handler functions are executed, and if necessary, virtual activities are created. The processed array will create a square matrix.

Limitations

• This library currently only supports one handler for multifunctional activities. Support for variable handlers will be added in a later release.

• This library is not yet integrated with bw2data - therefore, multifunctional activities must be manually converted:

import brightway2 as bw
import multifunctional as mf

mf.convert_multifunctional_activity(
    activity=bw.get_activity(("some", "activity")),
    handler="some_handling_function_label",
)

• This library current only works with the default SQlite backend

Installation

Install via conda or pip.

Contributing

Your contribution is welcome! Please follow the pull request workflow, even for minor changes.

When contributing to this repository with a major change, please first discuss the change you wish to make via issue, email, or any other method with the owners of this repository.

Please note we have a code of conduct, please follow it in all your interactions with the project.

Documentation and coding standards

• Black formatting
• Semantic versioning

Maintainers

• Chris Mutel

License

BSD-3-Clause. Copyright 2020 Chris Mutel.