Keras callback

keras_callback_medium_1.py

from keras.callbacks import Callback
import numpy as np

class MyCallback(Callback):
    def __init__(self, test_data, test_label, log_file=None, verbose=True):
        self.test_data = test_data
        self.test_label = test_label
        self.result = []
        self.log = open(log_file, 'w') if log_file else None
        self.verbose = verbose

    def on_epoch_end(self, epoch, logs=None):
        probs = self.model.predict(self.test_data)
        avg_acc = calculate_acc(probs, self.test_label)  # function to calculate acc
        self.result.append(avg_acc)
        log_str = 'Epoch {} acc= {:.4f}'.format(epoch, avg_acc)
        if self.verbose:
            print(log_str)
        if self.log:
            print(log_str, file=self.log)

    def on_train_end(self, logs=None):
        if self.log:
            self.log.close()