Snakenet.rb now applies modifications to the weights in both directions (e.g. positive and negative), creating two new AIs.

src/tools/snakenet/snakenet.rb

@@ -244,31 +244,45 @@ class AI
 	
 	def evolve
 		w = @weights.dup
-		action = rand(5)
-		if action==0 #swap
-			i1 = rand(network_size())
-			i2 = rand(network_size())
-			temp = w[i1]
-			w[i1] = w[i2]
-			w[i2] = temp
-		elsif action==1 #change single value
+		action = rand(4)
+		#if action==0 #swap
+		#	i1 = rand(network_size())
+		#	i2 = rand(network_size())
+		#	temp = w[i1]
+		#	w[i1] = w[i2]
+		#	w[i2] = temp
+		if action==0 #change single value
 			i = rand(network_size())
-			w[i] = rand() * 2 - 1.0
-		elsif action==2 #invert single value
+			diff = rand() * 0.2 - 0.1
+			w2 = w.dup
+			w[i] += diff
+			w[i] = 1.0 if w[i]>1.0
+			w[i] = -1.0 if w[i]<-1.0
+			w2[i] -= diff
+			w2[i] = 1.0 if w2[i]>1.0
+			w2[i] = -1.0 if w2[i]<-1.0
+			return [AI.new(w), AI.new(w2)]
+		elsif action==1 #invert single value
 			i = rand(network_size())
 			w[i] *= -1.0
-		elsif action==3
+		elsif action==2
 			(0...network_size()).each do |i|
 				w[i] = rand() * 2 - 1.0 if rand(5)==0
 			end
 		else #change multiple values
+			w2 = w.dup
 			(0...network_size()).each do |i|
 				if (rand(5)==0)
-					w[i] += rand() / 5.0 - 0.1
+					diff = rand() * 0.2 - 0.1
+					w[i] += diff
 					w[i] = 1.0 if w[i]>1.0
 					w[i] = -1.0 if w[i]<-1.0
+					w2[i] -= diff
+					w2[i] = 1.0 if w2[i]>1.0
+					w2[i] = -1.0 if w2[i]<-1.0
 				end
 			end
+			return [AI.new(w), AI.new(w2)]
 		end
 		
 		return AI.new(w)
@@ -389,6 +403,7 @@ loop do
 	10.times do
 		ais << AI.new
 	end
+	ais = ais.flatten
 	round+=1
 end
 rescue SystemExit, Interrupt