Polynomials

Example App

Checkout my Example App to see the gem in action!

Usage

require 'polynomials'
require 'gnuplot'
include Polynomials


polynomial = Polynomial.parse(ARGV[0])

points =  polynomial.roots | polynomial.local_extrema | polynomial.inflection_points

max_x =  points.max_by(&:x)
min_x =  points.min_by(&:x)
max_x = max_x == 0 ? max_x.x : 1
min_x = min_x == 0 ? min_x.x : -1

difference = (max_x-min_x).abs

start = min_x - difference/4.0
stop = max_x + difference/4.0
step = (start-stop).abs/1000.0

pointset = polynomial.pointset(start,stop,step)
data_x=  pointset.map(&:first)
data_y = pointset.map(&:last)

Gnuplot.open do |gp|
  Gnuplot::Plot.new(gp) do |plot|
    plot.xrange "[#{start}:#{stop}]"
    plot.title  "Polynomial"
    plot.ylabel "f(x)"
    plot.xlabel "x"
    plot.grid
    plot.data << Gnuplot::DataSet.new( [data_x,data_y] ) do |ds|
      ds.with = "lines"
      ds.linewidth = 0.2
      ds.title =  "f(x) = #{polynomial}"
      ds.smooth
    end

    [:inflection_point,:root, :maximum, :minimum].each do |kind_of_point|
      selected_points = points.select(&:"#{kind_of_point}?")
      plot.data << Gnuplot::DataSet.new([selected_points.map(&:x), selected_points.map(&:y)]) do |ds|
        ds.with = "points"
        ds.linewidth = 2
        ds.title = kind_of_point.to_s.pluralize.titleize
      end
    end
  end
end

Bash Command

 % ruby examples/plot_only_mutual_data.rb '20.432 x^4 - 17.75 x^3 - 20x^2 + 5 x -50'

Output:

Contributing to polynomials

Check out the latest master to make sure the feature hasn't been implemented or the bug hasn't been fixed yet
Check out the issue tracker to make sure someone already hasn't requested it and/or contributed it
Fork the project
Commit and push until you are happy with your contribution
Make sure to add tests for it. This is important so I don't break it in a future version unintentionally.
Please try not to mess with the Rakefile, version, or history. If you want to have your own version, or is otherwise necessary, that is fine, but please isolate to its own commit so I can cherry-pick around it.

Polynomials

Example App

Usage

Bash Command

Output:

Contributing to polynomials

Copyright