我已經使用CNN訓練了MNIST
的模型,但是當我在訓練後用測試數據檢查模型的準確性時,我發現我的準確性會提高。這是代碼。TensorFlow:多次評估測試集,但得到不同的準確性
BATCH_SIZE = 50
LR = 0.001 # learning rate
mnist = input_data.read_data_sets('./mnist', one_hot=True) # they has been normalized to range (0,1)
test_x = mnist.test.images[:2000]
test_y = mnist.test.labels[:2000]
def new_cnn(imageinput, inputshape):
weights = tf.Variable(tf.truncated_normal(inputshape, stddev = 0.1),name = 'weights')
biases = tf.Variable(tf.constant(0.05, shape = [inputshape[3]]),name = 'biases')
layer = tf.nn.conv2d(imageinput, weights, strides = [1, 1, 1, 1], padding = 'SAME')
layer = tf.nn.relu(layer)
return weights, layer
tf_x = tf.placeholder(tf.float32, [None, 28 * 28])
image = tf.reshape(tf_x, [-1, 28, 28, 1]) # (batch, height, width, channel)
tf_y = tf.placeholder(tf.int32, [None, 10]) # input y
# CNN
weights1, layer1 = new_cnn(image, [5, 5, 1, 32])
pool1 = tf.layers.max_pooling2d(
layer1,
pool_size=2,
strides=2,
) # -> (14, 14, 32)
weight2, layer2 = new_cnn(pool1, [5, 5, 32, 64]) # -> (14, 14, 64)
pool2 = tf.layers.max_pooling2d(layer2, 2, 2) # -> (7, 7, 64)
flat = tf.reshape(pool2, [-1, 7 * 7 * 64]) # -> (7*7*64,)
hide = tf.layers.dense(flat, 1024, name = 'hide') # hidden layer
output = tf.layers.dense(hide, 10, name = 'output')
loss = tf.losses.softmax_cross_entropy(onehot_labels=tf_y, logits=output) # compute cost
accuracy = tf.metrics.accuracy(labels=tf.argmax(tf_y, axis=1), predictions=tf.argmax(output, axis=1),)[1]
train_op = tf.train.AdamOptimizer(LR).minimize(loss)
sess = tf.Session()
init_op = tf.group(tf.global_variables_initializer(), tf.local_variables_initializer()) # the local var is for accuracy
sess.run(init_op) # initialize var in graph
saver = tf.train.Saver()
for step in range(101):
b_x, b_y = mnist.train.next_batch(BATCH_SIZE)
_, loss_ = sess.run([train_op, loss], {tf_x: b_x, tf_y: b_y})
if step % 50 == 0:
print(loss_)
accuracy_, loss2 = sess.run([accuracy, loss], {tf_x: test_x, tf_y: test_y })
print('Step:', step, '| test accuracy: %f' % accuracy_)
爲了簡化問題,我只使用了100次訓練迭代。測試集的最終準確度大約爲0.655000
。
但是當我運行下面的代碼:
for i in range(5):
accuracy2 = sess.run(accuracy, {tf_x: test_x, tf_y: test_y })
print(sess.run(weight2[1,:,0,0])) # To show that the model parameters won't update
print(accuracy2)
輸出是
[-0.06928255 -0.13498515 0.01266837 0.05656774 0.09438231]
0.725875
[-0.06928255 -0.13498515 0.01266837 0.05656774 0.09438231]
0.7684
[-0.06928255 -0.13498515 0.01266837 0.05656774 0.09438231]
0.79675
[-0.06928255 -0.13498515 0.01266837 0.05656774 0.09438231]
0.817
[-0.06928255 -0.13498515 0.01266837 0.05656774 0.09438231]
0.832187
這使我困惑,有人可以告訴我,什麼是錯的? 感謝您的耐心等待!
[每個推理的相同預測](https://stackoverflow.com/questions/44952929/same-prediction-for-each-inference) – user1735003
請包括完整的代碼。例如wgat你使用keep_prob? – lejlot
@lejlot抱歉,我刪除了冗餘部分。 – DennngP