lib/polynomials.rb in polynomials-0.1.5 vs lib/polynomials.rb in polynomials-0.1.6

@@ -1,9 +1,11 @@
 require 'set'
 require_relative 'term'
 require_relative 'core_ext/math'
+
 class Polynomial
+
   MinMaxMapping = { 1.0 => :max, -1.0  => :min }
   AfterextremaCurvatureMapping = { max: :right, min: :left }
   NegPosMinMaxExtremumMapping = {[1.0,-1.0] => :max,[-1.0,1.0] => :min}
 
   attr_accessor :terms
@@ -33,18 +35,10 @@
       end
       new_function.terms.reject! { |_,t| t.coefficient == 0 }
     return new_function
   end
 
-  def alter
-    new_function = self.class.new
-    self.terms.values.each do |term|
-      yield new_function, term
-    end
-    return new_function
-  end
-
   def roots
     if terms.keys.none?(&:zero?)
       self.alter { |nf, term| nf.terms[term.exponent-1].coefficient = term.coefficient }.roots << 0.0
     else
       case self.degree
@@ -63,12 +57,12 @@
   end
 
   def local_extrema
     derivative = self.derivative
     max_min_extremum =  Hash.new { |hash,key| hash[key] = Set.new }
-    unless derivative.degree == 0 
-      possible_extrema = derivative.roots.sort
+    possible_extrema = derivative.roots.sort
+    unless possible_extrema.empty?
 
       samples = ([possible_extrema.first - 1] + possible_extrema.sort + [possible_extrema.last + 1]).each_cons(2).map do |before,after|
         (before + after)/2
       end
 
@@ -118,13 +112,24 @@
     extrema[MinMaxMapping[max_or_min.last]] << 1.0/0
     return extrema
   end
 
  private
+
   def coefficients_till(n)
     coefficients = []
     (0..n).each do |e|
       coefficients << self.terms[e].coefficient
     end
     return coefficients.reverse
+  end
+
+ protected
+
+  def alter
+    new_function = self.class.new
+    self.terms.values.each do |term|
+      yield new_function, term
+    end
+    return new_function
   end
 end