validate.py 文件源码

def scores(output, target, threshold=0.5):
    # Count true positives, true negatives, false positives and false negatives.
    outputr = (output > threshold).long()
    target = target.long()
    a_sum = 0.0
    p_sum = 0.0
    r_sum = 0.0
    f2_sum = 0.0

    def _safe_size(t, n=0):
        if n < len(t.size()):
            return t.size(n)
        else:
            return 0

    count = 0
    for o, t in zip(outputr, target):
        tp = _safe_size(torch.nonzero(o * t))
        tn = _safe_size(torch.nonzero((o - 1) * (t - 1)))
        fp = _safe_size(torch.nonzero(o * (t - 1)))
        fn = _safe_size(torch.nonzero((o - 1) * t))
        a = (tp + tn) / (tp + fp + fn + tn)
        if tp == 0 and fp == 0 and fn == 0:
            p = 1.0
            r = 1.0
            f2 = 1.0
        elif tp == 0 and (fp > 0 or fn > 0):
            p = 0.0
            r = 0.0
            f2 = 0.0
        else:
            p = tp / (tp + fp)
            r = tp / (tp + fn)
            f2 = (5 * p * r) / (4 * p + r)
        a_sum += a
        p_sum += p
        r_sum += r
        f2_sum += f2
        count += 1
    accuracy = a_sum / count
    precision = p_sum / count
    recall = r_sum / count
    fmeasure = f2_sum / count
    return accuracy, precision, recall, fmeasure