Vgg-16 在尝试训练 MNIST 数据集时产生错误

Vgg-16 generating errors when trying to train MNIST dataset

我正在尝试在 MNIST 数据集上使用 Tensorflow 和 Keras 创建一个 Vgg-16 模型。 我已成功构建模型,但在训练我的 MNIST 数据集时出现错误。 我已经检查了这个错误的不同解决方案,但它似乎不起作用,因为我是这个领域的新手

Errors generated

ValueError: in user code:

    /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:805 train_function  *
        return step_function(self, iterator)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:795 step_function  **
        outputs = model.distribute_strategy.run(run_step, args=(data,))
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/distribute/distribute_lib.py:1259 run
        return self._extended.call_for_each_replica(fn, args=args, kwargs=kwargs)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/distribute/distribute_lib.py:2730 call_for_each_replica
        return self._call_for_each_replica(fn, args, kwargs)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/distribute/distribute_lib.py:3417 _call_for_each_replica
        return fn(*args, **kwargs)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:788 run_step  **
        outputs = model.train_step(data)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/training.py:756 train_step
        y, y_pred, sample_weight, regularization_losses=self.losses)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/engine/compile_utils.py:203 __call__
        loss_value = loss_obj(y_t, y_p, sample_weight=sw)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/losses.py:152 __call__
        losses = call_fn(y_true, y_pred)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/losses.py:256 call  **
        return ag_fn(y_true, y_pred, **self._fn_kwargs)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/util/dispatch.py:201 wrapper
        return target(*args, **kwargs)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/losses.py:1537 categorical_crossentropy
        return K.categorical_crossentropy(y_true, y_pred, from_logits=from_logits)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/util/dispatch.py:201 wrapper
        return target(*args, **kwargs)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/keras/backend.py:4833 categorical_crossentropy
        target.shape.assert_is_compatible_with(output.shape)
    /usr/local/lib/python3.6/dist-packages/tensorflow/python/framework/tensor_shape.py:1134 assert_is_compatible_with
        raise ValueError("Shapes %s and %s are incompatible" % (self, other))

    ValueError: Shapes (None, 10, 10) and (None, 2) are incompatible

Model buildup

model = Sequential()

model.add(Conv2D(input_shape=(input_shape),filters=64,kernel_size=(3,3),padding="same", activation="relu"))
model.add(Conv2D(filters=64,kernel_size=(3,3),padding="same", activation="relu"))
model.add(MaxPool2D(pool_size=(2,2),strides=(2,2)))

model.add(Conv2D(filters=128, kernel_size=(3,3), padding="same", activation="relu"))
model.add(Conv2D(filters=128, kernel_size=(3,3), padding="same", activation="relu"))
model.add(MaxPool2D(pool_size=(2,2),strides=(2,2)))

model.add(Conv2D(filters=256, kernel_size=(3,3), padding="same", activation="relu"))
model.add(Conv2D(filters=256, kernel_size=(3,3), padding="same", activation="relu"))
model.add(Conv2D(filters=256, kernel_size=(3,3), padding="same", activation="relu"))
model.add(MaxPool2D(pool_size=(2,2),strides=(2,2)))

model.add(Conv2D(filters=512, kernel_size=(3,3), padding="same", activation="relu"))
model.add(Conv2D(filters=512, kernel_size=(3,3), padding="same", activation="relu"))
model.add(Conv2D(filters=512, kernel_size=(3,3), padding="same", activation="relu"))
model.add(MaxPool2D(pool_size=(2,2),strides=(2,2)))


model.add(Conv2D(filters=512, kernel_size=(3,3), padding="same", activation="relu"))
model.add(Conv2D(filters=512, kernel_size=(3,3), padding="same", activation="relu"))
model.add(Conv2D(filters=512, kernel_size=(3,3), padding="same", activation="relu"))
model.add(MaxPool2D(pool_size=(2,2),strides=(2,2), padding='same'))


model.add(Flatten())


model.add(Dense(units=4096,activation="relu")); model.add(Dropout(0.5))
model.add(Dense(units=4096,activation="relu")); model.add(Dropout(0.5))
model.add(Dense(units=2, activation="softmax"))

# Compile the Model
model.compile(optimizer='adam', loss=keras.losses.categorical_crossentropy, metrics=['accuracy'])

MNISt Dataset

mnist = tf.keras.datasets.mnist
(X_train, Y_train), (X_test, Y_test) = mnist.load_data()

#processing
rows, cols = 28, 28
X_train = X_train.reshape(X_train.shape[0], rows, cols, 1)
X_test = X_test.reshape(X_test.shape[0], rows, cols, 1)
input_shape = (rows, cols, 1)

Y_train = tf.keras.utils.to_categorical(Y_train, 10)
Y_test = tf.keras.utils.to_categorical(Y_test, 10)

#  Normalize
X_train = X_train.astype('float32')
X_test = X_test.astype('float32')
X_train = X_train / 255.0
X_test = X_test / 255.0

training

history = model.fit(X_train, Y_train,
                     batch_size= 128,
                     epochs= 5,
                     verbose= 1)

最后一层应该输出 10 个值,因为 MNIST 包含 10 个 类。

model.add(Dense(units=10, activation="softmax"))

我复制了你的代码并运行它。一旦将顶层更改为具有 10 个神经元,它就可以正常运行。但是你的模型训练不好。我在下面提供了一个训练良好的简单模型。我还将您的测试集作为验证集包括在内。代码如下

model = tf.keras.Sequential([
    Conv2D(16, 3, padding='same', activation='relu', input_shape=input_shape ),
    MaxPooling2D(strides=1),
    Conv2D(32, 3, padding='same', activation='relu'),
    MaxPooling2D(strides=1),
    Conv2D(64, 3, padding='same', activation='relu'),
    MaxPooling2D(strides=1),
    Conv2D(128, 3, padding='same', activation='relu'),
    MaxPooling2D(strides=1),
    Conv2D(256, 3, padding='same', activation='relu'),
    MaxPooling2D(strides=1),
    Flatten(),
    Dense(128, activation='relu'),
    Dropout(.3),
    Dense(64, activation='relu'),
    Dropout(.3),
    Dense(10, activation='softmax')
])
model.compile(optimizer='adam', loss=keras.losses.categorical_crossentropy, metrics=['accuracy'])
print (model.summary())
val_data=(X_test, Y_test)
history = model.fit(X_train, Y_train, validation_data=val_data,
                     batch_size= 128,
                     epochs= 5,
                     verbose= 1)
# after 5  epochs result is accuracy: 0.9883  - val_accuracy: 0.9915