metric.py 2.01 KB

import os
import numpy as np
from sklearn.metrics import roc_curve, auc, average_precision_score, f1_score,classification_report,confusion_matrix
from scipy.optimize import brentq
from scipy.interpolate import interp1d
import matplotlib.pyplot as plt


def evaluate(labels, scores,res_th=None, saveto=None):
    '''
    metric for auc/ap
    :param labels:
    :param scores:
    :param res_th:
    :param saveto:
    :return:
    '''
    fpr = dict()
    tpr = dict()
    roc_auc = dict()

    # True/False Positive Rates.
    fpr, tpr, ths = roc_curve(labels, scores)
    roc_auc = auc(fpr, tpr)

    # Equal Error Rate
    eer = brentq(lambda x: 1. - x - interp1d(fpr, tpr)(x), 0., 1.)

    if saveto:
        plt.figure()
        lw = 2
        plt.plot(fpr, tpr, color='darkorange', lw=lw, label='(AUC = %0.2f, EER = %0.2f)' % (roc_auc, eer))
        plt.plot([eer], [1-eer], marker='o', markersize=5, color="navy")
        plt.plot([0, 1], [1, 0], color='navy', lw=1, linestyle=':')
        plt.xlim([0.0, 1.0])
        plt.ylim([0.0, 1.05])
        plt.xlabel('False Positive Rate')
        plt.ylabel('True Positive Rate')
        plt.title('Receiver operating characteristic')
        plt.legend(loc="lower right")
        plt.savefig(os.path.join(saveto, "ROC.pdf"))
        plt.close()

    # best f1
    best_f1 = 0
    best_threshold = 0
    for threshold in ths:
        tmp_scores = scores.copy()
        tmp_scores[tmp_scores >= threshold] = 1
        tmp_scores[tmp_scores < threshold] = 0
        cur_f1 = f1_score(labels, tmp_scores)
        if cur_f1 > best_f1:
            best_f1 = cur_f1
            best_threshold = threshold


    #threshold f1
    if res_th is not None and saveto is  not None:
        tmp_scores = scores.copy()
        tmp_scores[tmp_scores >= res_th] = 1
        tmp_scores[tmp_scores < res_th] = 0
        print(classification_report(labels,tmp_scores))
        print(confusion_matrix(labels,tmp_scores))
    auc_prc=average_precision_score(labels,scores)
    return auc_prc,roc_auc,best_threshold,best_f1