support Ruby 1.8.7: remove ruby 1.9 specific syntax, ignore narray fo…

…r JRuby platform, fix log(num, 2) for ruby 1.8.7

Rakefile

@@ -1,5 +1,4 @@
 require "bundler/gem_tasks"
-require_relative "lib/histogram/version"
 
 require 'rspec/core'
 require 'rspec/core/rake_task'

histogram.gemspec

@@ -19,12 +19,16 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
 
 
-  [ "bundler ~> 1.3", 
+  [ "bundler ~> 1.3",
     "rake ~> 10.1.0",
     "simplecov ~> 0.7.1",
     "rspec ~> 2.13.0",
-    "narray",
+    "rdoc"
   ].each do |argline|
     spec.add_development_dependency *argline.split(' ', 2).compact
   end
+
+  unless RUBY_PLATFORM =~ /java/
+    spec.add_development_dependency "narray"
+  end
 end

lib/histogram.rb

@@ -1,5 +1,11 @@
 
-class NArray 
+class NArray
+end
+
+unless Math.respond_to?(:log2)
+  def Math.log2(num)
+    Math.log(num, 2)
+  end
 end
 
 module Histogram
@@ -44,8 +50,8 @@ def sample_stats(obj)
     #     :sorted => false
     #   
     def iqrange(obj, opts={})
-      opt = {method: DEFAULT_QUARTILE_METHOD, sorted: false}.merge( opts )
-      srted = opt[:sorted] ? obj : obj.sort 
+      opt = {:method => DEFAULT_QUARTILE_METHOD, :sorted => false}.merge( opts )
+      srted = opt[:sorted] ? obj : obj.sort
       sz = srted.size
       answer = 
         case opt[:method]
@@ -89,9 +95,9 @@ def number_of_bins(methd=DEFAULT_BIN_METHOD, quartile_method=DEFAULT_QUARTILE_ME
           (mean, stddev) = Histogram.sample_stats(self) 
           range / ( 3.5*stddev*(self.size**(-1.0/3)) )
         when :sturges
-          1 + Math::log(self.size, 2)
+          1 + Math::log2(self.size)
         when :fd
-          2 * Histogram.iqrange(self, method: quartile_method) * (self.size**(-1.0/3))
+          2 * Histogram.iqrange(self, :method => quartile_method) * (self.size**(-1.0/3))
         end
       nbins = 1 if nbins <= 0
       nbins = 1 if nbins.nan?

spec/histogram_spec.rb

@@ -2,6 +2,16 @@
 
 require 'histogram'
 
+class Float
+  def round(n=nil)
+    if n
+      ((n**10) * self).to_i/(10**n)
+    else
+      super()
+    end
+  end
+end
+
 RSpec::Matchers.define :be_within_rounding_error_of do |expected|
   match do |actual|
     (act, exp) = [actual, expected].map {|ar| ar.collect {|v| v.to_f.round(8) } }
@@ -91,14 +101,14 @@
 end
 
 describe Histogram do
-  tmp = { 
-    obj0: (0..10).to_a,
-    obj1: [0, 1, 1.5, 2.0, 5.0, 6.0, 7, 8, 9, 9],
-    obj2: [-1, 0, 1, 1.5, 2.0, 5.0, 6.0, 7, 8, 9, 9, 10], 
-    obj3: [1, 1, 2, 2, 3, 3, 4, 4, 4],
-    obj4: [2, 2, 2, 2, 2, 4],
-    obj5: [1,2,3,3,3,4,5,6,7,8],
-    obj6: [0,0,0,0,0]
+  tmp = {
+    :obj0 => (0..10).to_a,
+    :obj1 => [0, 1, 1.5, 2.0, 5.0, 6.0, 7, 8, 9, 9],
+    :obj2 => [-1, 0, 1, 1.5, 2.0, 5.0, 6.0, 7, 8, 9, 9, 10],
+    :obj3 => [1, 1, 2, 2, 3, 3, 4, 4, 4],
+    :obj4 => [2, 2, 2, 2, 2, 4],
+    :obj5 => [1,2,3,3,3,4,5,6,7,8],
+    :obj6 => [0,0,0,0,0]
   }
   data = tmp.each {|k,v| [k, v.map(&:to_f).extend(Histogram)] }
 
@@ -112,12 +122,12 @@
     it_behaves_like 'something that can histogram'
   end
 
-  have_narray = 
+  have_narray =
     begin
       require 'narray'
       NArray.respond_to?(:to_na)
       true
-    rescue
+    rescue LoadError
       false
     end
 
@@ -152,16 +162,15 @@
     end
 
     it 'calculates the interquartile range via moore_mccabe' do
-      Histogram.iqrange(even, method: :moore_mccabe).should == 4.0
-      Histogram.iqrange(odd, method: :moore_mccabe).should == 4.0
+      Histogram.iqrange(even, :method => :moore_mccabe).should == 4.0
+      Histogram.iqrange(odd, :method => :moore_mccabe).should == 4.0
     end
 
     it 'calculates the interquartile range via tukey' do
-      Histogram.iqrange(even, method: :tukey).should == 4.0
-      Histogram.iqrange(odd, method: :tukey).should == 3.0
+      Histogram.iqrange(even, :method => :tukey).should == 4.0
+      Histogram.iqrange(odd, :method => :tukey).should == 3.0
     end
 
 
   end
 end
-