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Feature #15869

Add abs to Matrix

Added by bonafernando (Fernando Wolf Bona) 27 days ago. Updated 27 days ago.

Status:
Open
Priority:
Normal
Target version:
-
[ruby-core:92803]

Description

While I was studying Markov Chain I had to find the maximum absolute value of the Matrix to divide the matrix in numbers from 0 to 1 to be able to make further analysis. Like this:

q = Matrix[ ... ]
max = q.to_a.flatten.map { |e| e.abs }.max
q = q / max

So this is the first of two features that I would like to contribute.

  1. Matrix.abs
  2. Matrix.max

History

#1

Updated by bonafernando (Fernando Wolf Bona) 27 days ago

  • Backport deleted (2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN)
  • Tracker changed from Bug to Feature

Updated by bonafernando (Fernando Wolf Bona) 27 days ago

bonafernando (Fernando Wolf Bona) wrote:

While I was studying Markov Chain I had to find the maximum absolute value of the Matrix to divide the matrix in numbers from 0 to 1 to be able to make further analysis. Like this:

q = Matrix[ ... ]
max = q.to_a.flatten.map { |e| e.abs }.max
q = q / max

So this is the first of two features that I would like to contribute.

  1. Matrix.abs
  2. Matrix.max

PR: https://github.com/ruby/ruby/pull/2199

Updated by marcandre (Marc-Andre Lafortune) 27 days ago

  • Assignee set to marcandre (Marc-Andre Lafortune)

Updated by shevegen (Robert A. Heiler) 27 days ago

Interesting. Not sure if this has to do with Markov Chain per se, but for storing state
through automata (in bioinformatics), hidden markov models are also used. Perhaps
extending Matrix may be beneficial in general (for ruby as a larger ecosystem;
curiously enough, the third most often downloaded gem is diff-lcs, which is probably
useful in a variety of different applications; I came to it indirectly through Hamming
and Levensthein distances).

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