see fbeta

def fbeta_np(preds, targs, beta, thresh=0.5, epsilon=1e-8):
    """ see fbeta """
    assert beta > 0, 'beta needs to be greater than 0'
    beta2 = beta ** 2
    rec = recall_np(preds, targs, thresh)
    prec = precision_np(preds, targs, thresh)
    return (1 + beta2) * prec * rec / (beta2 * prec + rec + epsilon)