Disagreement measure between two classifiers

How often do two classifiers get different examples right?

An ensemble only helps when its members make different mistakes. The disagreement measure compares two classifiers on the same examples, using only whether each one was correct.

Let N_ab count the examples where classifier 1 has correctness a and classifier 2 has correctness b (1 means correct, 0 means wrong). The disagreement measure is (N_01 + N_10) / N, where N is the number of examples.

Implement disagreement(correct_a, correct_b), where both inputs are 1-D boolean or 0/1 arrays of the same length. Return the disagreement as a float between 0 and 1.

Constraints

• Both inputs must be 1-D and the same length. Otherwise raise ValueError.
• Empty inputs raise ValueError.
• Do not modify the inputs.

Hints