You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: compute_performance.rb
    path of file: ./repos/powerstation/powerstation/IDE_plugin/out/production/resources/static-analyzer/controller_model_analysis
    
    the code of the file until where you have to start completion: def compute_performance(output_dir, start_class, start_function, build_node_list_only=false)
	log_filename = "#{$app_dir}/#{start_class}_#{sta
    
def slicing(ns)
	nodes = Array.new
	used_nodes = Array.new
	ns.each do |n|
		used_nodes.push(n)
		nodes.push(n)
	end
	while(nodes.length > 0)
		node = nodes.pop
		if node.instance_of?Dataflow_edge
			next
		end