Pinned

1. pca.rb pca.rb

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   # This script implements a very basic PCA (Principal Component Analysis).

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   # PCAs are often used as statistical method on data sets to reduce

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   # dimensionality / complexity. This is done by finding new features which

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   # maximize variance. PCAs can reduce dimensionality down to any number,

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   # but lose information within the process. However, most of the time,

2. boids.rb boids.rb

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   # This script simulates flocking behavior of boids (bird-oid objects), based

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   # on Craig Reynolds algorithm. Also inspired by: https://eater.net/boids.

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   # It could probably be better optimized for performance, e.g. by using

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   # Quadtrees. Utilizing the 'matrix' library for vector operations didn't

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   # seem to improve speed.

3. phone_unlock_patterns.rb phone_unlock_patterns.rb

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   # This script calculates all possible paths through mobile phone unlock codes.

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   # Results are sorted in a depth first manner. There are exactly 389,498

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   # valid paths. However, Android only allows paths with length > 3, resulting

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   # in only 389,112 paths[1].

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   #

4. needleman_wunsch.rb needleman_wunsch.rb

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   # This script is an implementation of the Needleman-Wunsch algorithm for

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   # sequence alignment (mostly used for nucleotide or protein sequences in

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   # bioinformatics). The algorithm works by first computing a similarity matrix

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   # and then backtrack the optimal paths. The scores/penalties for matches,

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   # mismatches and gaps can be set. Complexity is O(n*m) where n and m are the

5. viterbi.rb viterbi.rb

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   # This script is a simple implementation of the famous Viterbi algorithm.

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   # Viterbi can find the best path of states through an HMM (Hidden Markov Model),

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   # given a sequence of observations. In the future, the HMM class could be

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   # extended to also support other algorithms (e.g. Forward or Baum-Welch).

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   #

6. pile_of_sand.rb pile_of_sand.rb

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   # This script implements a simple cellular automaton which simulates sand,

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   # inspired by the game "Noita".

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   #

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   class PileOfSand

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     attr_reader :width, :height