code: protected Confusion evaluate( Map<String,List<String>> set ) {
  		ClassificationHistogram histogram = new ClassificationHistogram(scenes.size());
  
  		int total = 0;
  		for (int i = 0; i < scenes.size(); i++) {
  			total += set.get(scenes.get(i)).size();
  		}
  		System.out.println("total images "+total);
  
  		for (int i = 0; i < scenes.size(); i++) {
  			String scene = scenes.get(i);
  
  			List<String> images = set.get(scene);
  			System.out.println("  "+scene+" "+images.size());
  			for (String image : images) {
  				int predicted = classify(image);
  				histogram.increment(i, predicted);
  			}
  		}
  
  		return histogram.createConfusion();
  	}
docs: Given a set of images with known classification, predict which scene each one belongs in and compute
  a confusion matrix for the results.
  
  @param set Set of classified images
  @return Confusion matrix