在莫煩Python教程的“Dropout 解決 overfitting”一節中，出現錯誤如下：
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"]()]]
代碼如下：
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#從0到9的圖片 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中沒有加入keep_prob的key和value
sess.run(train_step,feed_dict={xs:X_train,ys:y_train,keep_prob:0.5})中，沒有寫入keep_prob:0.5
造成feed_dict和placeholder的對應問題，但改正后，仍報該錯誤。反復檢查了幾遍，並沒有發現問題。
最后實在無解，關閉了Spyder和anaconda，再打開anaconda和Spyder，居然可以正常運行了。。
但是也只是第一次可以正常運行，當刪了生成的log文件，再次運行時，仍報該錯誤..至於為什么第二次運行就又報錯仍未解決。
雖然問題不大，但是改了feed_dict后，問題還是沒能解決，被困擾了一天，因此記錄一下。