Ejemplo n.º 1
0
def modelselection_grid_search_kernel():
    num_subsets = 3
    num_vectors = 20
    dim_vectors = 3

    # create some (non-sense) data
    matrix = rand(dim_vectors, num_vectors)

    # create num_feautres 2-dimensional vectors
    features = RealFeatures()
    features.set_feature_matrix(matrix)

    # create labels, two classes
    labels = Labels(num_vectors)
    for i in range(num_vectors):
        labels.set_label(i, 1 if i % 2 == 0 else -1)

    # create svm
    classifier = LibSVM()

    # splitting strategy
    splitting_strategy = StratifiedCrossValidationSplitting(
        labels, num_subsets)

    # accuracy evaluation
    evaluation_criterion = ContingencyTableEvaluation(ACCURACY)

    # cross validation class for evaluation in model selection
    cross = CrossValidation(classifier, features, labels, splitting_strategy,
                            evaluation_criterion)
    cross.set_num_runs(1)

    # print all parameter available for modelselection
    # Dont worry if yours is not included, simply write to the mailing list
    classifier.print_modsel_params()

    # model parameter selection
    param_tree = create_param_tree()
    param_tree.print_tree()

    grid_search = GridSearchModelSelection(param_tree, cross)

    print_state = True
    best_combination = grid_search.select_model(print_state)
    print("best parameter(s):")
    best_combination.print_tree()

    best_combination.apply_to_machine(classifier)

    # larger number of runs to have tighter confidence intervals
    cross.set_num_runs(10)
    cross.set_conf_int_alpha(0.01)
    result = cross.evaluate()
    print("result: ")
    result.print_result()

    return 0
def modelselection_grid_search_kernel():
	num_subsets=3
	num_vectors=20
	dim_vectors=3

	# create some (non-sense) data
	matrix=rand(dim_vectors, num_vectors)

	# create num_feautres 2-dimensional vectors
	features=RealFeatures()
	features.set_feature_matrix(matrix)

	# create labels, two classes
	labels=BinaryLabels(num_vectors)
	for i in range(num_vectors):
		labels.set_label(i, 1 if i%2==0 else -1)

	# create svm
	classifier=LibSVM()

	# splitting strategy
	splitting_strategy=StratifiedCrossValidationSplitting(labels, num_subsets)

	# accuracy evaluation
	evaluation_criterion=ContingencyTableEvaluation(ACCURACY)

	# cross validation class for evaluation in model selection
	cross=CrossValidation(classifier, features, labels, splitting_strategy, evaluation_criterion)
	cross.set_num_runs(1)

	# print all parameter available for modelselection
	# Dont worry if yours is not included, simply write to the mailing list
	classifier.print_modsel_params()

	# model parameter selection
	param_tree=create_param_tree()
	param_tree.print_tree()

	grid_search=GridSearchModelSelection(param_tree, cross)

	print_state=True
	best_combination=grid_search.select_model(print_state)
	print("best parameter(s):")
	best_combination.print_tree()

	best_combination.apply_to_machine(classifier)

	# larger number of runs to have tighter confidence intervals
	cross.set_num_runs(10)
	cross.set_conf_int_alpha(0.01)
	result=cross.evaluate()
	print("result: ")
	result.print_result()

	return 0