https://github.com/stefansalewski/quickhulldisk
Convex hull of disks in 2d
https://github.com/stefansalewski/quickhulldisk
Last synced: 6 months ago
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Convex hull of disks in 2d
- Host: GitHub
- URL: https://github.com/stefansalewski/quickhulldisk
- Owner: StefanSalewski
- Created: 2021-04-27T05:59:15.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2021-04-27T07:30:48.000Z (over 4 years ago)
- Last Synced: 2025-02-06T04:46:07.380Z (8 months ago)
- Language: Nim
- Size: 17.6 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
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Metadata Files:
- Readme: README.adoc
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README
= Quick Hull of Disks in 2D
:icons: font
:imagesdir: http://ssalewski.de/tmp
:source-highlighter: rouge
:rouge-style: molokai
== This is the first Nim implementation of the QuickHullDisk algorithm
The Nim code follows very closely the C++ implementation available at
https://github.com/vdrc/The-Source-Code-and-Benchmark-Dataset-for-QuickhullDisk
and described in
https://www.sciencedirect.com/science/article/pii/S0096300319306186
License and copyright are the same as for the C++ implementation:
Contributors: Chanyoung Song, Joonghyun Ryu, and Deok-Soo Kim.
As following all the math in the paper exactly is not that easy
I have created a first
implementation which follows the C++ code very closely. The Nim code
contains already the recent fixes of the C++ repository which avoids the crashes
for disks with radius zero. The Nim code stores the disks currently as value types
in sequences, as this was the easiest way to get it working. Changing this to
reference types or list like container types may improve the performance.
The original C++ package provides data sets with test input and output files.
This Nim packages contains a simple test called filetest.nim which
gets an input and an output file from the C++ package, calculates the hull
from the input and compares the result to the provided output file.
For those people who wonder what this is all about and why one should need it:
In 2d geometry finding the convex hull of a set of disks is a not that uncommon
problem. Disks can be obstacles or way marks in path finding problems.
Naive algorithm can fail for some disk arrangements or may be very slow.
From my knowledge the first discussion of the problem was in the Davenport paper
from 1997, followed by a few more publications.
Another reliable solution for this problem is based on the Apollonius graph, which is
provided by the CGAL C++ library.
My intended application for this package is an experimental rubberband topological printed circuit
board auto-router. The initial version was written in Ruby language and used the CGAL Apollonius graph.
The Nim rubber-band router may use this package, but later routers may use strongly customized versions
written from scratch following the original paper.