README.markdown in polynomials-0.3.0 vs README.markdown in polynomials-0.4.0

@@ -2,54 +2,53 @@
 
 ## Usage
 
 <pre><code>
 require 'polynomials'
-  require 'gnuplot'
-  include Polynomials
+require 'gnuplot'
+include Polynomials
 
 
-  polynomial = Polynomial.parse(ARGV[0])
+polynomial = Polynomial.parse(ARGV[0])
 
-  points =  polynomial.roots | polynomial.local_extrema | polynomial.inflection_points
+points =  polynomial.roots | polynomial.local_extrema | polynomial.inflection_points
 
-  max_x =  points.max_by(&amp;:x).x
-  min_x =  points.min_by(&amp;:x).x
+max_x =  points.max_by(&amp;:x).x
+min_x =  points.min_by(&amp;:x).x
 
-  start = (min_x - 0.1)
-  stop = (max_x + 0.1)
+start = (min_x - min_x.abs/2)
+stop = (max_x + max_x.abs/2)
 
-  x = start
-  data_x,data_y = [],[]
-  while x &lt; stop
-    data_x &lt;&lt; x
-    data_y &lt;&lt; polynomial.(x)
-    x += 0.005
-  end
+step = (max_x-min_x).abs/200
 
-  Gnuplot.open do |gp|
-    Gnuplot::Plot.new(gp) do |plot|
-      plot.xrange &quot;[#{start}:#{stop}]&quot;
-      plot.title  &quot;Polynomial&quot;
-      plot.ylabel &quot;f(x)&quot;
-      plot.xlabel &quot;x&quot;
-      plot.grid
-      plot.data &lt;&lt; Gnuplot::DataSet.new( [data_x,data_y] ) do |ds|
-        ds.with = &quot;lines&quot;
-        ds.linewidth = 0.1
-        ds.title =  &quot;f(x) = #{polynomial}&quot;
-      end
+pointset = polynomials.pointset(start,stop,step)
 
-      [:inflection_point,:root, :maximum, :minimum].each do |kind_of_point|
-        selected_points = points.select(&amp;:&quot;#{kind_of_point}?&quot;)
-        plot.data &lt;&lt; Gnuplot::DataSet.new([selected_points.map(&amp;:x), selected_points.map(&amp;:y)]) do |ds|
-          ds.with = &quot;points&quot;
-          ds.linewidth = 2
-          ds.title = kind_of_point.to_s.pluralize.titleize
-        end
+data_x = pointset.map(&:x)
+data_y = pointset.map(&:y)
+
+Gnuplot.open do |gp|
+  Gnuplot::Plot.new(gp) do |plot|
+    plot.xrange &quot;[#{start}:#{stop}]&quot;
+    plot.title  &quot;Polynomial&quot;
+    plot.ylabel &quot;f(x)&quot;
+    plot.xlabel &quot;x&quot;
+    plot.grid
+    plot.data &lt;&lt; Gnuplot::DataSet.new( [data_x,data_y] ) do |ds|
+      ds.with = &quot;lines&quot;
+      ds.linewidth = 0.2
+      ds.title =  &quot;f(x) = #{polynomial}&quot;
+    end
+
+    [:inflection_point,:root, :maximum, :minimum].each do |kind_of_point|
+      selected_points = points.select(&amp;:&quot;#{kind_of_point}?&quot;)
+      plot.data &lt;&lt; Gnuplot::DataSet.new([selected_points.map(&amp;:x), selected_points.map(&amp;:y)]) do |ds|
+        ds.with = &quot;points&quot;
+        ds.linewidth = 2
+        ds.title = kind_of_point.to_s.pluralize.titleize
       end
     end
   end
+end
 </code></pre>
 
 ### Bash Command
 <pre><code> % ruby examples/plot_only_mutual_data.rb '20.432 x^4 - 17.75 x^3 - 20x^2 + 5 x -50'</code></pre>