1. A non-transitory computer-readable medium storing computer-executable instructions that when executed by a computer cause the computer to perform a method, the method comprising: receiving an input data sample for classification as belonging to one of two possible classes, where the input data sample includes a set of attribute values; and evaluating the set of attribute values with a tree function that defines a decision boundary of a classification tree, the tree function classifying an input data sample as belonging to one of the two possible classes based, at least in part, on attribute values of the input data sample; and determining a classification of the input data sample based on an output of the tree function.