Refactor mandelbrot, seems to run quicker

Author: monkstone

contributed/library/simple_complex/simple_complex.rb

@@ -0,0 +1,21 @@
+require 'forwardable'
+
+# A simpler complex class
+class SimpleComplex
+  extend Forwardable
+  attr_reader :complex
+  def_delegator :@complex, :to_s
+  def_delegators :@complex, :abs, :+, :*
+
+  def initialize(real, complex)
+    @complex = Complex(real, complex)
+  end
+
+  def add!(other)
+    @complex += other.complex
+  end
+
+  def square!
+    @complex *= complex
+  end
+end

contributed/mandelbrot.rb

@@ -1,8 +1,10 @@
 # Mandelbrot Set example
-# by Jordan Scales (http://jordanscales.com)
-# Modified to use map1d (instead of map), and somewhat
-# optimized (update_pixels instead of set, and hypot for abs)
-# no need to loop
+# after an original by Jordan Scales (http://jordanscales.com)
+# Modified to use simple_complex library, instead of a custom Complex also uses
+# map1d (instead of map), and a somewhat optimized (update_pixels instead of
+# set), and using grid, rather than nested loops
+
+load_library :simple_complex
 
 def setup
   sketch_title 'Mandelbrot'
@@ -12,69 +14,31 @@ def setup
 
 # main drawing method
 def draw
-  (0...900).each do |x|
-    (0...600).each do |y|
-      c = Complex.new(map1d(x, (0...900), (-3..1.5)), map1d(y, (0...600), (-1.5..1.5)))
-      # mandel will return 0 to 20 (20 is strong)
-      #   map this to 0, 255 (and flip it)
-      pixels[x + y * 900] = color(255 - map1d(mandel(c, 20), (0..20), (0..255)).to_i)
-    end
+  grid(900, 600) do |x, y|
+    c = SimpleComplex.new(
+      map1d(x, (0...900), (-3..1.5)), map1d(y, (0...600), (-1.5..1.5))
+    )
+    # mandel will return 0..20 (20 is strong) map this to 255..0 (NB: reverse)
+    pixels[x + y * 900] = color(map1d(mandel(c, 20), (0..20), (255..0)).to_i)
   end
   update_pixels
 end
 
 # calculates the "accuracy" of a given point in the mandelbrot set
-#    : how many iterations the number survives without becoming chaotic
+# how many iterations the number survives without becoming chaotic
 def mandel(z, max = 10)
   score = 0
   c = z.clone
   while score < max
     # z = z^2 + c
-    z.square
-    z.add c
+    z.square!
+    z.add! c
     break if z.abs > 2
     score += 1
   end
   score
 end
 
-# rolled my own Complex class
-# including only the functionality I need (abs, square, add, to_s)
-#
-# Using this class, runs in ~12.5s on my MacBook Air
-# compared to ~22s using ruby's Complex struct
-class Complex
-  attr_accessor :real, :imag
-
-  def initialize(real, imag)
-    @real = real
-    @imag = imag
-  end
-
-  # squares a complex number - overwriting it
-  def square
-    r = real * real - imag * imag
-    i = 2 * real * imag
-    @real = r
-    @imag = i
-  end
-
-  # adds a given complex number
-  def add(c)
-    @real += c.real
-    @imag += c.imag
-  end
-
-  # computes the magnitude (HelperMethods dist is a safer version of Math.hypot)
-  def abs
-    dist(0, 0, real, imag)
-  end
-
-  def to_s
-    format('(%f+%fi)', real, imag)
-  end
-end
-
 def settings
   size 900, 600
 end