https://github.com/thinkphp/dijkstra.gem

A Gem for Dijkstra's algorithm Shortest Path Finder.
https://github.com/thinkphp/dijkstra.gem

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A Gem for Dijkstra's algorithm Shortest Path Finder.

• Host: GitHub
• URL: https://github.com/thinkphp/dijkstra.gem
• Owner: thinkphp
• Created: 2014-09-12T20:08:36.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2016-04-28T14:48:04.000Z (almost 10 years ago)
• Last Synced: 2025-01-19T21:41:45.829Z (about 1 year ago)
• Language: Ruby
• Homepage: https://rubygems.org/gems/dijkstra
• Size: 22.5 KB
• Stars: 7
• Watchers: 3
• Forks: 7
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# Dijkstra's Algorithm 

[ ![Image](https://badge.fury.io/rb/dijkstra.svg "Image title") ](https://rubygems.org/gems/dijkstra "Badge")

Dijkstra's algorithm, conceived by computer scientist Edsger Dijkstra, is a graph search algorithm that solves in single-source

shortest path problem for a graph with non-negative edge path costs, producing a shortest path tree. 

![Screenshot](http://farm6.staticflickr.com/5572/15142640541_6ea1eb3d48.jpg)

## Install

```

gem install dijkstra 

```

## Usage

```

require 'dijkstra'

# In this context we have 9 edges or paths.

r = [[1, 2, 1],

     [1, 3, 9],

     [1, 5, 3],

     [2, 4, 3],

     [2, 3, 7],

     [4, 3, 2],

     [4, 1, 1],

     [5, 2, 4],

     [5, 4, 2]]

start_point = 1 # starting node

end_point = 3 # arrival node

ob = Dijkstra.new(start_point, end_point, r)

puts "Cost = #{ob.cost}"

puts "Shortest Path from #{start_point} to #{end_point} = #{ob.shortest_path}"

ob.write_to_file('shortestpath.out')

=>  shortestpath.out =>

    Cost -> 6

    Shortest Path -> [1, 2, 4, 3]

```

> You can use any kind of element as node, not only numbers.

> If returned cost is Infinity, and returned shortest_path is the starting node, then there is no Path that connects starting node and arrival node.

## Manual Installation

```

$ git clone git://github.com/oscartanner/dijkstra.gem.git

$ cd dijkstra.gem

$ gem build dijkstra.gemspec

$ gem install ./dijkstra-0.1.0.gem

$ ruby app.rb # testing

$ Cost = 6

$ Shortest Path  = [1,2,4,3]=> true

```

## References

  http://en.wikipedia.org/wiki/Dijkstra%27s_algorithm