在莫烦Python教程的“Dropout 解决 overfitting”一节中，出现错误如下：
InvalidArgumentError: You must feed a value for placeholder tensor ‘Placeholder_1‘ with dtype float and shape [?,10]
runfile(‘E:/python/kerasTest/tfDropoutTest9.py‘, wdir=‘E:/python/kerasTest‘) C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\sklearn\cross_validation.py:41: DeprecationWarning: This module was deprecated in version 0.18 in favor of the model_selection module into which all the refactored classes and functions are moved. Also note that the interface of the new CV iterators are different from that of this module. This module will be removed in 0.20. "This module will be removed in 0.20.", DeprecationWarning) runfile(‘E:/python/kerasTest/tfDropoutTest9.py‘, wdir=‘E:/python/kerasTest‘) Traceback (most recent call last): File "<ipython-input-2-64f3a3bcd083>", line 1, in <module> runfile(‘E:/python/kerasTest/tfDropoutTest9.py‘, wdir=‘E:/python/kerasTest‘) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\spyder\utils\site\sitecustomize.py", line 710, in runfile execfile(filename, namespace) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\spyder\utils\site\sitecustomize.py", line 101, in execfile exec(compile(f.read(), filename, ‘exec‘), namespace) File "E:/python/kerasTest/tfDropoutTest9.py", line 67, in <module> train_result = sess.run(merged,feed_dict={xs:X_train,ys:y_train,keep_prob:1}) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tensorflow\python\client\session.py", line 895, in run run_metadata_ptr) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tensorflow\python\client\session.py", line 1128, in _run feed_dict_tensor, options, run_metadata) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tensorflow\python\client\session.py", line 1344, in _do_run options, run_metadata) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tensorflow\python\client\session.py", line 1363, in _do_call raise type(e)(node_def, op, message) InvalidArgumentError: You must feed a value for placeholder tensor ‘Placeholder_1‘ with dtype float and shape [?,10] [[Node: Placeholder_1 = Placeholder[dtype=DT_FLOAT, shape=[?,10], _device="/job:localhost/replica:0/task:0/device:CPU:0"]()]] Caused by op ‘Placeholder_1‘, defined at: File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\spyder\utils\ipython\start_kernel.py", line 241, in <module> main() File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\spyder\utils\ipython\start_kernel.py", line 237, in main kernel.start() File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\ipykernel\kernelapp.py", line 477, in start ioloop.IOLoop.instance().start() File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\zmq\eventloop\ioloop.py", line 177, in start super(ZMQIOLoop, self).start() File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tornado\ioloop.py", line 888, in start handler_func(fd_obj, events) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tornado\stack_context.py", line 277, in null_wrapper return fn(*args, **kwargs) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\zmq\eventloop\zmqstream.py", line 440, in _handle_events self._handle_recv() File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\zmq\eventloop\zmqstream.py", line 472, in _handle_recv self._run_callback(callback, msg) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\zmq\eventloop\zmqstream.py", line 414, in _run_callback callback(*args, **kwargs) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tornado\stack_context.py", line 277, in null_wrapper return fn(*args, **kwargs) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\ipykernel\kernelbase.py", line 283, in dispatcher return self.dispatch_shell(stream, msg) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\ipykernel\kernelbase.py", line 235, in dispatch_shell handler(stream, idents, msg) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\ipykernel\kernelbase.py", line 399, in execute_request user_expressions, allow_stdin) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\ipykernel\ipkernel.py", line 196, in do_execute res = shell.run_cell(code, store_history=store_history, silent=silent) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\ipykernel\zmqshell.py", line 533, in run_cell return super(ZMQInteractiveShell, self).run_cell(*args, **kwargs) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\IPython\core\interactiveshell.py", line 2698, in run_cell interactivity=interactivity, compiler=compiler, result=result) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\IPython\core\interactiveshell.py", line 2808, in run_ast_nodes if self.run_code(code, result): File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\IPython\core\interactiveshell.py", line 2862, in run_code exec(code_obj, self.user_global_ns, self.user_ns) File "<ipython-input-1-64f3a3bcd083>", line 1, in <module> runfile(‘E:/python/kerasTest/tfDropoutTest9.py‘, wdir=‘E:/python/kerasTest‘) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\spyder\utils\site\sitecustomize.py", line 710, in runfile execfile(filename, namespace) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\spyder\utils\site\sitecustomize.py", line 101, in execfile exec(compile(f.read(), filename, ‘exec‘), namespace) File "E:/python/kerasTest/tfDropoutTest9.py", line 39, in <module> ys = tf.placeholder(tf.float32,[None,10]) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tensorflow\python\ops\array_ops.py", line 1680, in placeholder return gen_array_ops._placeholder(dtype=dtype, shape=shape, name=name) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tensorflow\python\ops\gen_array_ops.py", line 4105, in _placeholder "Placeholder", dtype=dtype, shape=shape, name=name) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tensorflow\python\framework\op_def_library.py", line 787, in _apply_op_helper op_def=op_def) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tensorflow\python\framework\ops.py", line 3160, in create_op op_def=op_def) File "C:\Users\Admin\AppData\Local\conda\conda\envs\tensorflow\lib\site-packages\tensorflow\python\framework\ops.py", line 1625, in __init__ self._traceback = self._graph._extract_stack() InvalidArgumentError (see above for traceback): You must feed a value for placeholder tensor ‘Placeholder_1‘ with dtype float and shape [?,10] [[Node: Placeholder_1 = Placeholder[dtype=DT_FLOAT, shape=[?,10], _device="/job:localhost/replica:0/task:0/device:CPU:0"]()]]
代码如下：
import tensorflow as tf from sklearn.datasets import load_digits from sklearn.cross_validation import train_test_split from sklearn.preprocessing import LabelBinarizer #load data digits = load_digits() X = digits.data#从0到9的图片 y = digits.target y =LabelBinarizer().fit_transform(y) X_train,X_test,y_train,y_test = train_test_split(X,y,test_size=.3) def add_layer(inputs,in_size,out_size,layer_name,activation_function=None): #add one more layer and return the output of this layer Weights = tf.Variable(tf.random_normal([in_size,out_size])) biases = tf.Variable(tf.zeros([1, out_size]) + 0.1) Wx_plus_b = tf.matmul(inputs, Weights) + biases Wx_plus_b = tf.nn.dropout(Wx_plus_b,keep_prob) if activation_function is None: outputs = Wx_plus_b else: outputs = activation_function(Wx_plus_b) tf.summary.histogram(layer_name+‘/outputs‘,outputs) return outputs xs = tf.placeholder(tf.float32,[None,64])#8*8 ys = tf.placeholder(tf.float32,[None,10]) keep_prob = tf.placeholder(tf.float32) #add output layer l1 = add_layer(xs,64,50,‘l1‘,activation_function=tf.nn.tanh) prediction = add_layer(l1,50,10,‘l2‘,activation_function=tf.nn.softmax) #the loss between prediction and real data cross_entropy = tf.reduce_mean(-tf.reduce_sum(ys * tf.log(prediction), reduction_indices=[1]))#loss tf.summary.scalar(‘loss‘,cross_entropy) train_step = tf.train.GradientDescentOptimizer(0.6).minimize(cross_entropy) sess = tf.Session() merged = tf.summary.merge_all() train_writer = tf.summary.FileWriter("logs/train",sess.graph) test_writer = tf.summary.FileWriter("logs/test",sess.graph) sess.run(tf.global_variables_initializer()) for i in range(500): sess.run(train_step,feed_dict={xs:X_train,ys:y_train,keep_prob:0.5}) if i % 50 == 0: train_result = sess.run(merged,feed_dict={xs:X_train,ys:y_train,keep_prob:1}) test_result = sess.run(merged,feed_dict={xs:X_test,ys:y_test,keep_prob:1}) train_writer.add_summary(train_result,i) test_writer.add_summary(test_result,i)
原因：
在feed_dict中没有加入keep_prob的key和value
sess.run(train_step,feed_dict={xs:X_train,ys:y_train,keep_prob:0.5})中，没有写入keep_prob:0.5
造成feed_dict和placeholder的对应问题，但改正后，仍报该错误。反复检查了几遍，并没有发现问题。
最后实在无解，关闭了Spyder和anaconda，再打开anaconda和Spyder，居然可以正常运行了。。
但是也只是第一次可以正常运行，当删了生成的log文件，再次运行时，仍报该错误..至于为什么第二次运行就又报错仍未解决。