我使用tensorflow来运行cnn深度学习程序，但它失败了？我已将输入数据'images'翻译为np.float32，但它仍然报告dtype错误：
E tensorflow/core/client/tensor_c_api.cc:485] You must feed a value for placeholder tensor 'Placeholder_2' with dtype float
[[Node: Placeholder_2 = Placeholder[dtype=DT_FLOAT, shape=[], _device="/job:localhost/replica:0/task:0/cpu:0"]()]]
以下是我的代码：
import dataset
import numpy as np
import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data
mnist = input_data.read_data_sets("MNIST_data/", one_hot=True)
class CNN(object):
def __init__(self):
self.x = tf.placeholder(tf.float32, [None, 784])
self.y_ = tf.placeholder(tf.float32, [None, 10])
# First Convolutional Layer
W_conv1 = self.weight_variable([5, 5, 1, 32])
b_conv1 = self.bias_variable([32])
x_image = tf.reshape(self.x, [-1, 28, 28, 1])
h_conv1 = tf.nn.relu(self.conv2d(x_image, W_conv1) + b_conv1)
h_pool1 = self.max_pool_2x2(h_conv1)
# Second Convolutional Layer
W_conv2 = self.weight_variable([5, 5, 32, 64])
b_conv2 = self.bias_variable([64])
h_conv2 = tf.nn.relu(self.conv2d(h_pool1, W_conv2) + b_conv2)
h_pool2 = self.max_pool_2x2(h_conv2)
# Densely Connected Layer
W_fc1 = self.weight_variable([7 * 7 * 64, 1024])
b_fc1 = self.bias_variable([1024])
h_pool2_flat = tf.reshape(h_pool2, [-1, 7 * 7 * 64])
h_fc1 = tf.nn.relu(tf.matmul(h_pool2_flat, W_fc1) + b_fc1)
# Dropout
self.keep_prob = tf.placeholder(tf.float32)
h_fc1_drop = tf.nn.dropout(h_fc1, self.keep_prob)
# Readout Layer
W_fc2 = self.weight_variable([1024, 10])
b_fc2 = self.bias_variable([10])
self.y_conv = tf.matmul(h_fc1_drop, W_fc2) + b_fc2
# Train and Evaluate the Model
self.cross_entropy = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(self.y_conv, self.y_))
self.train_step = tf.train.AdamOptimizer(1e-4).minimize(self.cross_entropy)
self.correct_prediction = tf.equal(tf.argmax(self.y_conv, 1), tf.argmax(self.y_, 1))
self.accuracy = tf.reduce_mean(tf.cast(self.correct_prediction, tf.float32))
self.saver = tf.train.Saver()
self.sess = tf.Session()
self.sess.run(tf.initialize_all_variables())
print("cnn initial finished!")
def weight_variable(self, shape):
initial = tf.truncated_normal(shape, stddev=0.1)
return tf.Variable(initial)
def bias_variable(self, shape):
initial = tf.constant(0.1, shape=shape)
return tf.Variable(initial)
def conv2d(self, x, W):
return tf.nn.conv2d(x, W, strides=[1, 1, 1, 1], padding='SAME')
def max_pool_2x2(self, x):
return tf.nn.max_pool(x, ksize=[1, 2, 2, 1], strides=[1, 2, 2, 1], padding='SAME')
def train(self):
# 初始化数据集
self.trainset = dataset.Train()
# mnist_softmax.py 中使用的是在sess中通过run方法执行train_step, accuracy
# mnist_cnn.py中 使用的是直接执行train_step, accuracy.eval，所以必须要传入session参数
for i in range(20000):
batch_xs, batch_ys = mnist.train.next_batch(50)
if i%100 == 0:
#print(batch_xs[0])
#print(batch_ys[0])
self.train_accuracy = self.accuracy.eval(session=self.sess, feed_dict={self.x: batch_xs, self.y_: batch_ys, self.keep_prob: 1.0})
print("step %d, trainning accuracy %g" % (i, self.train_accuracy))
self.train_step.run(session=self.sess, feed_dict={self.x: batch_xs, self.y_: batch_ys, self.keep_prob: 0.5})
# Save the variables to disk.
save_path = self.saver.save(self.sess, "CNN_data/model.ckpt")
print("Model saved in file: %s" % save_path)
#print("test accuracy %g" % self.accuracy.eval(session=self.sess, feed_dict={self.x: mnist.test.images, self.y_: mnist.test.labels, self.keep_prob: 1.0}))
def predict(self, images):
images = np.reshape(images, (1, 784))
images = images.astype(np.float32)
print(images)
ckpt = tf.train.get_checkpoint_state("CNN_data/")
if ckpt and ckpt.model_checkpoint_path:
self.saver.restore(self.sess, ckpt.model_checkpoint_path)
else:
print("No checkpoint found!")
predictions = self.sess.run(self.y_conv, feed_dict={self.x: images})
return predictions
if __name__ == '__main__':
cnn = CNN()
#cnn.train()
images = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
cnn.predict(images)
列车方法没有问题，但是当调用预测时，总是会出现上述占位符dtype错误的错误？我不知道为什么因为我已经检查过我的imga是float32 dtype。
答案 0 :(得分：0)
如果它在这里失败了：
predictions = self.sess.run(self.y_conv, feed_dict={self.x: images})
这是因为你需要传入一个self.keep_prob