我在神经网络上的tensorflow中工作,试图最大化两个数据集之间的相关性:http://ttic.uchicago.edu/~klivescu/papers/andrew_icml2013.pdf
我有一个"损失"函数有点复杂所以我用numpy数组(并称之为corr_func())编写它,以便它可以使用张量运行我使用tf.py_func函数,我尝试以相同的方式更新渐变如此处所示How to make a custom activation function with only Python in Tensorflow?
给了我们以下代码
def omega_grad(op, grad):
x = op.inputs[0]
y = op.inputs[1]
n_gr1 = tf_omega_grad_H1(x,y)
n_gr2 = tf_omega_grad_H2 (x,y)
return grad * n_gr1, grad * n_gr2
这两个函数tf_omega_gradH1 / 2()是正确的,但有点长,这里要显示,但在本文中定义为给定两个输出的相关的偏导数。 然后将相关定义为
corr = py_func(corr_func, [H1,H2], tf.float32, stateful=True, name='assemblage',grad=omega_grad)
optimizer=tf.train.GradientDescentOptimizer(learning_rate).minimize(-corr)
事情是不行的,我试图运行优化器,它引发了以下错误:
InternalError (see above for traceback): Failed to run py callback pyfunc_31: see error log.
[[Node: gradients/assemblage_grad/PyFunc = PyFunc[Tin=[DT_FLOAT, DT_FLOAT], Tout=[DT_FLOAT], token="pyfunc_31", _device="/job:localhost/replica:0/task:0/cpu:0"](Reseau_de_neurone1/relu_layer_3, Reseau_de_neurone2/relu_layer_3)]]
如果我尝试通过运行来看到渐变,那么还有更多:
tf.gradients(corr,H1)
它返回None ...显然我不能很好地控制这个渐变更新,我也不知道如何解决这个错误。
注意:H1和H2是我的神经网络的两个输出
更新:错误的日志是:
Traceback (most recent call last):
File "<ipython-input-1-4ce1bb0cc21d>", line 1, in <module>
runfile('/home/zagdoun/Bureau/tutoTensorflow/NN.py', wdir='/home/zagdoun/Bureau/tutoTensorflow')
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/spyder/utils/site/sitecustomize.py", line 866, in runfile
execfile(filename, namespace)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/spyder/utils/site/sitecustomize.py", line 94, in execfile
builtins.execfile(filename, *where)
File "/home/zagdoun/Bureau/tutoTensorflow/NN.py", line 344, in <module>
_, c= sess.run([optimizer, corr],feed_dict={X : batch_X, Y : batch_Y})
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/client/session.py", line 778, in run
run_metadata_ptr)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/client/session.py", line 982, in _run
feed_dict_string, options, run_metadata)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/client/session.py", line 1032, in _do_run
target_list, options, run_metadata)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/client/session.py", line 1052, in _do_call
raise type(e)(node_def, op, message)
InternalError: Failed to run py callback pyfunc_1: see error log.
[[Node: gradients/assemblage_grad/PyFunc = PyFunc[Tin=[DT_FLOAT, DT_FLOAT], Tout=[DT_FLOAT], token="pyfunc_1", _device="/job:localhost/replica:0/task:0/cpu:0"](Reseau_de_neurone1/relu_layer_3, Reseau_de_neurone2/relu_layer_3)]]
Caused by op u'gradients/assemblage_grad/PyFunc', defined at:
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/spyder/utils/ipython/start_kernel.py", line 227, in <module>
main()
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/spyder/utils/ipython/start_kernel.py", line 223, in main
kernel.start()
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/ipykernel/kernelapp.py", line 474, in start
ioloop.IOLoop.instance().start()
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/zmq/eventloop/ioloop.py", line 177, in start
super(ZMQIOLoop, self).start()
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tornado/ioloop.py", line 887, in start
handler_func(fd_obj, events)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tornado/stack_context.py", line 275, in null_wrapper
return fn(*args, **kwargs)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/zmq/eventloop/zmqstream.py", line 440, in _handle_events
self._handle_recv()
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/zmq/eventloop/zmqstream.py", line 472, in _handle_recv
self._run_callback(callback, msg)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/zmq/eventloop/zmqstream.py", line 414, in _run_callback
callback(*args, **kwargs)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tornado/stack_context.py", line 275, in null_wrapper
return fn(*args, **kwargs)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/ipykernel/kernelbase.py", line 276, in dispatcher
return self.dispatch_shell(stream, msg)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/ipykernel/kernelbase.py", line 228, in dispatch_shell
handler(stream, idents, msg)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/ipykernel/kernelbase.py", line 390, in execute_request
user_expressions, allow_stdin)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/ipykernel/ipkernel.py", line 196, in do_execute
res = shell.run_cell(code, store_history=store_history, silent=silent)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/ipykernel/zmqshell.py", line 501, in run_cell
return super(ZMQInteractiveShell, self).run_cell(*args, **kwargs)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2717, in run_cell
interactivity=interactivity, compiler=compiler, result=result)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2827, in run_ast_nodes
if self.run_code(code, result):
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2881, in run_code
exec(code_obj, self.user_global_ns, self.user_ns)
File "<ipython-input-1-4ce1bb0cc21d>", line 1, in <module>
runfile('/home/zagdoun/Bureau/tutoTensorflow/NN.py', wdir='/home/zagdoun/Bureau/tutoTensorflow')
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/spyder/utils/site/sitecustomize.py", line 866, in runfile
execfile(filename, namespace)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/spyder/utils/site/sitecustomize.py", line 94, in execfile
builtins.execfile(filename, *where)
File "/home/zagdoun/Bureau/tutoTensorflow/NN.py", line 324, in <module>
optimizer=tf.train.GradientDescentOptimizer(learning_rate).minimize(-corr)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/training/optimizer.py", line 315, in minimize
grad_loss=grad_loss)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/training/optimizer.py", line 386, in compute_gradients
colocate_gradients_with_ops=colocate_gradients_with_ops)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/ops/gradients_impl.py", line 560, in gradients
grad_scope, op, func_call, lambda: grad_fn(op, *out_grads))
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/ops/gradients_impl.py", line 368, in _MaybeCompile
return grad_fn() # Exit early
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/ops/gradients_impl.py", line 560, in <lambda>
grad_scope, op, func_call, lambda: grad_fn(op, *out_grads))
File "/home/zagdoun/Bureau/tutoTensorflow/NN.py", line 278, in omega_grad
n_gr1 = tf_omega_grad_H1(x,y)
File "/home/zagdoun/Bureau/tutoTensorflow/NN.py", line 267, in tf_omega_grad_H1
z = tf.py_func(omega_grad_H1, [X,Y],tf.float32, stateful=True)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/ops/script_ops.py", line 189, in py_func
input=inp, token=token, Tout=Tout, name=name)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/ops/gen_script_ops.py", line 40, in _py_func
name=name)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/framework/op_def_library.py", line 768, in apply_op
op_def=op_def)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 2336, in create_op
original_op=self._default_original_op, op_def=op_def)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 1228, in __init__
self._traceback = _extract_stack()
...which was originally created as op u'assemblage', defined at:
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/spyder/utils/ipython/start_kernel.py", line 227, in <module>
main()
[elided 19 identical lines from previous traceback]
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/spyder/utils/site/sitecustomize.py", line 94, in execfile
builtins.execfile(filename, *where)
File "/home/zagdoun/Bureau/tutoTensorflow/NN.py", line 323, in <module>
corr = py_func(assemblage, [H1,H2], tf.float32, stateful=True, name='assemblage',grad=omega_grad)
File "/home/zagdoun/Bureau/tutoTensorflow/NN.py", line 223, in py_func
return tf.py_func(func, inp, Tout, stateful=stateful, name=name)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/ops/script_ops.py", line 189, in py_func
input=inp, token=token, Tout=Tout, name=name)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/ops/gen_script_ops.py", line 40, in _py_func
name=name)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/framework/op_def_library.py", line 768, in apply_op
op_def=op_def)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 2336, in create_op
original_op=self._default_original_op, op_def=op_def)
File "/home/zagdoun/anaconda2/lib/python2.7/site-packages/tensorflow/python/framework/ops.py", line 1228, in __init__
self._traceback = _extract_stack()
InternalError (see above for traceback): Failed to run py callback pyfunc_1: see error log.
[[Node: gradients/assemblage_grad/PyFunc = PyFunc[Tin=[DT_FLOAT, DT_FLOAT], Tout=[DT_FLOAT], token="pyfunc_1", _device="/job:localhost/replica:0/task:0/cpu:0"](Reseau_de_neurone1/relu_layer_3, Reseau_de_neurone2/relu_layer_3)]]
答案 0 :(得分:1)
根据我的解释,py_func函数不能传播渐变,但是,您可以手动指定渐变。
import numpy as np
import tensorflow as tf
# Define custom py_func which takes also a grad op as argument:
def py_func(func, inp, Tout, stateful=True, name=None, grad=None):
# Need to generate a unique name to avoid duplicates:
rnd_name = 'PyFuncGrad' + str(np.random.randint(0, 1E+8))
tf.RegisterGradient(rnd_name)(grad) # see _MySquareGrad for grad example
g = tf.get_default_graph()
with g.gradient_override_map({"PyFunc": rnd_name}):
return tf.py_func(func, inp, Tout, stateful=stateful, name=name)
Hense有意义的是你不能用tf.gradients(corr,H1)或GradientDescentOptimizer传播渐变。