Welcome to kep_solver’s documentation!
kep_solver
This Python package is devoted to various algorithms, procedures and mechanisms that are useful when studying kidney exchange programmes in general. It is written and maintained by William Pettersson
Quick start
Create a virtual environment for kep_solver
mkvirtualenv kep_solver
Install kep_solver
pip install kep_solver
Download a sample JSON file from
https://kep-web.optimalmatching.com/static/jsons/sample-1.json
Run the following Python commands
# Import the required functions
from kep_solver.fileio import read_json
from kep_solver.pool import Pool
from kep_solver.model import TransplantCount
# Read some input
instance = read_json("sample-1.json")
# Create a transplant pool with one objective
pool = Pool([TransplantCount()])
# Cycles can have at most 3 donor/recipient pairs, and chains can have at most
# 2 donors (i.e., one non-directed donor and one donor/recipient pair)
solution = pool.solve_single(instance, maxCycleLength=3, maxChainLength=2)
# Print the solution
for selected in solution.selected:
print(f"Selected {selected}")
Current features
Reading instance files (json and XML formats)
Creation of compatibility graphs
Solving for the following objectives (single, or hierarchical)
Maximise the number of transplants
Maximise the number of backarcs
Maximise the number of effective 2-way exchanges
Minimise the number of three-cycles
Maximise the score using the UK scoring mechanisms
While the above objectives are exactly those in use by NHSBT when running the UKLKSS (the UK national KEP), I do intend to add further objectives
Expected users
I see two classes of users of this software:
Researchers - Depending on what questions you want answered, you can either test policy changes to determine how they affect the running of a KEP, or you can implement new models or objectives to see how they perform
Health care institutes - I have tried to make this software as robust as possible, but for now I cannot guarantee any particular level of performance or any exact optimality of a solution. If you do want to use this software for real-world impact, feel free to get in touch and I may be able to help.
Interface
This is just a Python module for now, a web-interface that demonstrates a basic use case is viewable at https://kep-web.optimalmatching.com, and the source code for said website is online at https://gitlab.com/wpettersson/kep_web
Future plans
More objective functions
Random instance generation
Simulating the development of a KEP over time
Supporting transnational pools
Implementation of faster models and modelling techniques
Contributing
I welcome input from others, whether you have ideas for improvements or want to submit code. Either get in touch directly, or raise an issue
Acknowledgements
This software has been supported by the Engineering and Physical Sciences Research Council (EPSRC) grant EP/T004878/1 (Multilayer Algorithmics to Leverage Graph Structure).