TensorFlow 无法为 Tensor 'Placeholder:0' 提供形状值 (100, 784) [英] TensorFlow Cannot feed value of shape (100, 784) for Tensor 'Placeholder:0'
问题描述
我正在学习 TensorFlow.因此,为了了解如何制作某些东西,我尝试从源代码中复制一些代码并执行它.但是我遇到了错误消息.所以我尝试了这个网站的一些解决方案,但它不起作用(我在评论中保留了我的测试).
I am learning TensorFLow. So to understand how to make something, I tried to copy some code from a source and execute it. But I'm hitting an error message. So I tried some solution from this website but it does not work (I kept my test in comments).
"""programme 1 """
import tensorflow as tf
import numpy as np
from tensorflow.examples.tutorials.mnist import input_data
mnist = input_data.read_data_sets('MNIST_data', one_hot=True)
X = tf.placeholder(tf.float32,[None, 28, 28, 1]) #28 * 28 taille image 1 = 1pixel car noir et blanc "X" valeur
W = tf.Variable(tf.zeros([784, 10])) # 28*28 = 784 , 10 -> 0 à 9 "W" = weight = poid
b = tf.Variable(tf.zeros([10])) #chiffre de 0 à 9 a reconnaitre "b" = constante
init = tf.initialize_all_variables()
#model
Y = tf.nn.softmax(tf.matmul(tf.reshape(X,[-1, 784]), W) + b) #fonction "matmul": produit matriciel "-1": reussite obligatoire
#Place holder
Y_ = tf.placeholder(tf.float32, [None, 10])
#loss function
cross_entropy = -1 * tf.reduce_sum(Y_ * tf.log(Y)) #formule
# % of correct annwer found in batch
is_correct = tf.equal(tf.argmax(Y,1),tf.argmax(Y_,1))
accuracy = tf.reduce_mean(tf.cast(is_correct,tf.float32))
#training step
optimizer = tf.train.GradientDescentOptimizer(0.003) #petit pas
train_step = optimizer.minimize(cross_entropy)
sess = tf.Session()
sess.run(init)
for i in range(10000):
#load batch of image and ocrrects answer
batch_X, batch_Y = mnist.train.next_batch(100)
batch_X = np.reshape(batch_X, (-1, 784))
#batch_Y = np.reshape(batch_Y, (-1, 784))
train_data = {X: batch_X, Y_: batch_Y}
#train
sess.run(train_step, feed_dict=train_data)
a,c = sess.run([accuracy,cross_entropy],feed = train_data)
test_data = {X:mnist.test.images, Y_:mnist.test.labels}
a,c = sess.run([accuracy,cross_entropy],feed = test_data)
日志:
Traceback (most recent call last):
File "d: ensorflow est1.py", line 46, in <module>
sess.run(train_step, feed_dict=train_data)
File "C:UsersProprietaireAppDataLocalProgramsPythonPython35libsite-packages ensorflowpythonclientsession.py", line 895, in run
run_metadata_ptr)
File "C:UsersProprietaireAppDataLocalProgramsPythonPython35libsite-packages ensorflowpythonclientsession.py", line 1100, in _run
% (np_val.shape, subfeed_t.name, str(subfeed_t.get_shape())))
ValueError: Cannot feed value of shape (100, 784) for Tensor 'Placeholder:0', which has shape '(?, 28, 28, 1)'
2017-08-30 19:07:37.406994: W C: f_jenkinshomeworkspace
el-winMwindowsPY35 ensorflowcoreplatformcpu_feature_guard.cc:45] The TensorFlow library wasn't compiled to use AVX instructions, but these are available on your machine and could speed up CPU computations.
第 46 行是
sess.run(train_step, feed_dict=train_data)
我该怎么做才能解决这个错误?
What can I do to resolve this error?
推荐答案
您收到该错误是因为您输入的内容与 TensorFlow 预期的内容不匹配.要解决此问题,您可能需要将 placeholder:0
处的数据重新整形,即 batch_X
(?, 28, 28, 1)
.例如,您将执行以下操作:
You are getting that error because there is a mismatch between the shape of what you are feeding in and what the TensorFlow is expecting. To fix the issue, you might want to reshape your data at placeholder:0
which is batch_X
to
(?, 28, 28, 1)
. For example, you would do the following:
batch_X = np.reshape(batch_X, (-1, 28, 28, 1))
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