add graph generation in PNG

examples/tsp.rb

@@ -1,9 +1,10 @@
 # frozen_string_literal: true
 
-# bundle exec ruby --jit examples/tsp.rb --dot
+# bundle exec ruby --jit examples/tsp.rb --dot --png
 $LOAD_PATH.unshift File.expand_path('../lib', __dir__)
 
 require 'optparse'
+require 'open3'
 require 'alns'
 require 'alns/state'
 require 'alns/accept/hill_climbing'
@@ -14,24 +15,35 @@
 
 module TSP
   def self.solve
-    write_dot = false
     seed = 1234
+    max_iterations = 2000
+    write_dot = false
+    write_png = false
     secure_random = false
 
     OptionParser.new do |parser|
       parser.banner = 'Usage: tsp.rb [options]'
 
-      parser.on('-d', '--dot', 'write a dot file with the result') do
-        write_dot = true
-      end
-
       parser.on('-sSEED', '--seed=SEED', Integer, 'specify seed') do |v|
         seed = v
       end
 
+      parser.on('-iCOUNT', '--iteration-count=COUNT', Integer, 'iteration count') do |v|
+        max_iterations = v
+      end
+
       parser.on('-r', '--secure-random', 'use secure random') do
         secure_random = true
       end
+
+      parser.on('-d', '--dot', 'create a dot file with the result') do
+        write_dot = true
+      end
+
+      parser.on('-g', '--png', 'create a png file with the result') do
+        write_png = true
+        write_dot = true
+      end
     end.parse!
 
     nodes = make_nodes(COORDS)
@@ -69,7 +81,7 @@ def self.solve
 
     select = ALNS::Select::RouletteWheel.new([3, 2, 1, 0.5], 0.8, num_destroy, num_repair)
     accept = ALNS::Accept::HillClimbing.new
-    stop = ALNS::Stop::MaxIterations.new(2000)
+    stop = ALNS::Stop::MaxIterations.new(max_iterations)
     # stop = ALNS::Stop::MaxRuntime.new(2)
 
     start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
@@ -92,6 +104,7 @@ def self.solve
 
     # neato -Tpng tmp/tsp.dot -o tmp/tsp.png
     write_dot_file('tmp/tsp.dot', COORDS, result.best_state.edges) if write_dot
+    write_png_file('tmp/tsp.dot', 'tmp/tsp.png') if write_png
   end
 
   def self.operator_stats_to_s(counter)
@@ -435,6 +448,17 @@ def self.write_dot_file(filename, nodes, edges)
       f.puts '}'
     end
   end
+
+  def self.write_png_file(dotfile, pngfile)
+    stdout, stderr, status = Open3.capture3('neato', '-Tpng', dotfile, '-o', pngfile)
+    return if status.success?
+
+    puts "neato is failed with status: #{status}"
+    puts 'STDOUT:'
+    puts stdout
+    puts 'STDERR:'
+    puts stderr
+  end
 end
 
 TSP.solve if __FILE__ == $PROGRAM_NAME