Example #1
0
	def generate(number=10,r=0.5):
		"""Function to generate and return a random tree with fixed number of internal nodes added.  
		The root has to be a scalarizing node.  Biasing of the tree towards (or away from) binary
		nodes can be controlled with the parameter r."""
		root = ScalarNode(CGAFunctions.DataMethodFactory().getScalar())
		tree = AlgorithmTree(root)
		while number > 0:
			tNode = random.choice(tree.getTermini())
			fNode = CGAGenerator._getRandomFunctionalNode(r)
			CGAGenerator._extend(tNode,fNode)
			number -= 1
		return tree
Example #2
0
	def expgenerate(p,r=0.5):
		"""Generates and returns a random tree.  Current tree is extended at a *single* node with
		probability p, and process terminates with probability 1-p."""
		root = ScalarNode(CGAFunctions.DataMethodFactory().getScalar())
		tree = AlgorithmTree(root)
		extend = True
		while extend:
			tNode = random.choice(tree.getTermini())
			fNode = CGAGenerator._getRandomFunctionalNode(r)
			CGAGenerator._extend(tNode,fNode)
			if uniform() < p:
				extend = True
			else:
				extend = False
		return tree