Nearest neighbour algorithm

Nearest neighbour algorithm written in Elixir.

Installation

1. Add nearest_neighbour_algorithm to your list of dependencies in mix.exs:

def deps do
  [{:nearest_neighbour_algorithm, "~> 1.0.3"}]
end

Usage

Based on the Travelling salesman problem we create a list with all points, where we want to find the shortest route between them.

Example:

iex> map = [
  a: [a: 0.00, b: 5.12, c: 3.40, d: 9.63, e: 6.81],
  b: [a: 5.12, b: 0.00, c: 4.91, d: 6.85, e: 8.42],
  c: [a: 3.40, b: 4.91, c: 0.00, d: 6.67, e: 3.87],
  d: [a: 9.63, b: 6.85, c: 6.67, d: 0.00, e: 6.88],
  e: [a: 6.81, b: 8.42, c: 3.87, d: 6.88, e: 0.00]
]
iex> NearestNeighbourAlgorithm.shortest_route(map)
[:a, :c, :e, :d, :b, :a]

As you can see the map describes the distances between the points, it's the same like the following table:

	A	B	C	D	E
A	0	5.12	3.4	9.63	6.81
B	5.12	0	4.91	6.85	8.42
C	3.4	4.91	0	6.67	3.87
D	9.63	6.85	6.67	0	6.88
E	6.81	8.42	3.87	6.88	0

The algorithm will start to the first point, which is :a in our example. Then it will look up the nearest neighbour of :a, which is :c. He will move to :c and repeat the steps until every point has been reached. So in our example the shortest route is:

A - C - E - D - B - A.

License

The MIT License (MIT) Copyright (c) 2016 Henrik Fricke

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 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 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 copies or substantial portions of the Software.

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 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.