小编Arl*_*lex的帖子

训练开始时，运行窗口中仅显示loss和acc，缺少val_loss和val_acc。仅在最后才会显示这些值。

model.add(Flatten())
model.add(Dense(512, activation="relu"))
model.add(Dropout(0.5))
model.add(Dense(10, activation="softmax"))

model.compile(
    loss='categorical_crossentropy',
    optimizer="adam",
    metrics=['accuracy']
)

model.fit(
    x_train,
    y_train,
    batch_size=32, 
    epochs=1, 
    validation_data=(x_test, y_test),
    shuffle=True
)

训练是这样开始的：

Train on 50000 samples, validate on 10000 samples
Epoch 1/1

   32/50000 [..............................] - ETA: 34:53 - loss: 2.3528 - acc: 0.0938
   64/50000 [..............................] - ETA: 18:56 - loss: 2.3131 - acc: 0.0938
   96/50000 [..............................] - ETA: 13:45 - loss: 2.3398 - acc: 0.1146

这就是它完成的时候

49984/50000 [============================>.] - ETA: 0s - loss: 1.5317 - acc: 0.4377
50000/50000 [==============================] - …