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我想在 PyTorch-ignite 的自定义指标中使用 sklearn 的 f1_score。
我找不到好的解决方案。虽然在 PyTorch-ignite 的官网上，有一个解决方案

    precision = Precision(average=False)
    recall = Recall(average=False)
    F1 = Fbeta(beta=1.0, average=False, precision=precision, recall=recall)

，如果你需要有一个f1分数微/宏/加权，你可以不使用这个例子。

如何在 sklearn 库中使用自定义指标？

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1 回答 1

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解决方案是首先创建一个自定义指标：

import torch
from ignite.metrics import Metric
from sklearn.metrics import f1_score


class F1Score(Metric):

    def __init__(self, *args, **kwargs):
        self.f1 = 0
        self.count = 0
        super().__init__(*args, **kwargs)

    def update(self, output):
        y_pred, y = output[0].detach(), output[1].detach()

        _, predicted = torch.max(y_pred, 1)
        f = f1_score(y.cpu(), predicted.cpu(), average='micro')
        self.f1 += f
        self.count += 1

    def reset(self):
        self.f1 = 0
        self.count = 0
        super(F1Score, self).reset()

    def compute(self):
        return self.f1 / self.count

然后你可以使用它create_supervised_evaluator或create_supervised_trainer作为：

import logging

import torch
from ignite.engine import Events
from ignite.engine import create_supervised_evaluator
from ignite.metrics import Accuracy, Fbeta
from ignite.metrics.precision import Precision
from ignite.metrics.recall import Recall

from metrics.f1score import F1Score


def inference(
        cfg,
        model,
        val_loader
):
    device = cfg.MODEL.DEVICE

    logger = logging.getLogger("template_model.inference")
    logger.info("Start inferencing")

    precision = Precision(average=False)
    recall = Recall(average=False)
    F1 = Fbeta(beta=1.0, average=False, precision=precision, recall=recall)
    metrics = {'accuracy': Accuracy(),
               'precision': precision,
               'recall': recall,
               'custom': F1Score(),
               'f1': F1}
    evaluator = create_supervised_evaluator(model,
                                            metrics=metrics,
                                            device=device)

    # adding handlers using `evaluator.on` decorator API
    @evaluator.on(Events.EPOCH_COMPLETED)
    def print_validation_results(engine):
        metrics = evaluator.state.metrics
        metrics = evaluator.state.metrics

        _avg_accuracy = metrics['accuracy']

        _precision = metrics['precision']
        _precision = torch.mean(_precision)

        _recall = metrics['recall']
        _recall = torch.mean(_recall)

        _f1 = metrics['f1']
        _f1 = torch.mean(_f1)

        _custom = metrics['custom']
        logger.info(
            "Test Results - Epoch: {} Avg accuracy: {:.3f}, precision: {:.3f}, recall: {:.3f}, f1 score: {:.3f}, custom: {:.2f}".format(
                engine.state.epoch, _avg_accuracy, _precision, _recall, _f1, _custom))

    evaluator.run(val_loader)

结果是：

Test Results - Epoch: 1 Avg accuracy: 0.758, precision: 0.776, recall: 0.766, f1 score: 0.759, custom: 0.76
于 2021-06-28T07:48:42.667 回答