import pandas as pd
import numpy as np


def APE(actual, pred):
    """
    Calculate absolute percentage error.
    Returns a vector of APE values with same length as actual/pred.
    """
    return 100 * np.abs((actual - pred) / actual)


def MAPE(actual, pred):
    """
    Calculate mean absolute percentage error.
    Remove NA and values where actual is close to zero
    """
    not_na = ~(np.isnan(actual) | np.isnan(pred))
    not_zero = ~np.isclose(actual, 0.0)
    actual_safe = actual[not_na & not_zero]
    pred_safe = pred[not_na & not_zero]
    return np.mean(APE(actual_safe, pred_safe))