【发布时间】：2016-08-05 04:35:00
【问题描述】：
当我尝试运行我的 LSTM 程序（对于可变长度输入）时，我收到以下错误。
TypeError：扫描'scan_fn'的内部图表不一致：一个 输入和输出与相同的循环状态相关联，并且 应该具有相同的类型，但类型为 'TensorType(float64, col)' 和 'TensorType(float64, matrix)' 分别。
我的程序基于 imdb 情感分析问题的 LSTM 示例，如下所示：http://deeplearning.net/tutorial/lstm.html。我的数据不是 imdb 的，而是传感器数据。
我分享了我的源代码：lstm_var_length.py 和数据：data.npz。 （点击文件）
从上面的错误和一些谷歌搜索让我明白我的函数中的向量/矩阵维度存在一些问题。以下是出现此问题的函数定义：
def lstm_layer(shared_params, input_ex, options):
"""
LSTM Layer implementation. (Variable Length inputs)
Parameters
----------
shared_params: shared model parameters W, U, b etc
input_ex: input example (say dimension: 36 x 100 i.e 36 features and 100 time units)
options: Neural Network model options
Output / returns
----------------
output of each lstm cell [h_0, h_1, ..... , h_t]
"""
def slice(param, slice_no, height):
return param[slice_no*height : (slice_no+1)*height, :]
def cell(wxb, ht_1, ct_1):
pre_activation = tensor.dot(shared_params['U'], ht_1)
pre_activation += wxb
height = options['hidden_dim']
ft = tensor.nnet.sigmoid(slice(pre_activation, 0, height))
it = tensor.nnet.sigmoid(slice(pre_activation, 1, height))
c_t = tensor.tanh(slice(pre_activation, 2, height))
ot = tensor.nnet.sigmoid(slice(pre_activation, 3, height))
ct = ft * ct_1 + it * c_t
ht = ot * tensor.tanh(ct)
return ht, ct
wxb = tensor.dot(shared_params['W'], input_ex) + shared_params['b']
num_frames = input_ex.shape[1]
result, updates = theano.scan(cell,
sequences=[wxb.transpose()],
outputs_info=[tensor.alloc(numpy.asarray(0., dtype=floatX),
options['hidden_dim'], 1),
tensor.alloc(numpy.asarray(0., dtype=floatX),
options['hidden_dim'], 1)],
n_steps=num_frames)
return result[0] # only ht is needed
def build_model(shared_params, options):
"""
Build the complete neural network model and return the symbolic variables
Parameters
----------
shared_params: shared, model parameters W, U, b etc
options: Neural Network model options
return
------
x, y, f_pred_prob, f_pred, cost
"""
x = tensor.matrix(name='x', dtype=floatX)
y = tensor.iscalar(name='y') # tensor.vector(name='y', dtype=floatX)
num_frames = x.shape[1]
# lstm outputs from each cell
lstm_result = lstm_layer(shared_params, x, options)
# mean pool from the lstm cell outputs
pool_result = lstm_result.sum(axis=1)/(1. * num_frames)
# Softmax / Logistic Regression
pred = tensor.nnet.softmax(tensor.dot(shared_params['softmax_W'], pool_result) +
shared_params['softmax_b'])
# predicted probability function
theano.printing.debugprint(pred)
f_pred_prob = theano.function([x], pred, name='f_pred_prob', mode='DebugMode') # 'DebugMode' <-- Problem seems to occur at this point
# predicted class
f_pred = theano.function([x], pred.argmax(axis=0), name='f_pred')
# cost of the model: -ve log likelihood
offset = 1e-8 # an offset to prevent log(0)
cost = -tensor.log(pred[y-1, 0] + offset) # y = 1,2,...n but indexing is 0,1,..(n-1)
return x, y, f_pred_prob, f_pred, cost
上述错误是在尝试编译f_pred_prob theano函数时引起的。
异常和调用堆栈如下：
File "/home/inblueswithu/Documents/Theano_Trails/lstm_var_length.py", line 450, in
main()
File "/home/inblueswithu/Documents/Theano_Trails/lstm_var_length.py", line 447, in main
train_lstm(model_options, train, valid)
File "/home/inblueswithu/Documents/Theano_Trails/lstm_var_length.py", line 314, in train_lstm
(x, y, f_pred_prob, f_pred, cost) = build_model(shared_params, options)
File "/home/inblueswithu/Documents/Theano_Trails/lstm_var_length.py", line 95, in build_model
f_pred_prob = theano.function([x], pred, name='f_pred_prob', mode='DebugMode') # 'DebugMode'
File "/usr/local/lib/python2.7/dist-packages/theano/compile/function.py", line 320, in function
output_keys=output_keys)
File "/usr/local/lib/python2.7/dist-packages/theano/compile/pfunc.py", line 479, in pfunc
output_keys=output_keys)
File "/usr/local/lib/python2.7/dist-packages/theano/compile/function_module.py", line 1777, in orig_function
defaults)
File "/usr/local/lib/python2.7/dist-packages/theano/compile/debugmode.py", line 2571, in create
storage_map=storage_map)
File "/usr/local/lib/python2.7/dist-packages/theano/gof/link.py", line 690, in make_thunk
storage_map=storage_map)[:3]
File "/usr/local/lib/python2.7/dist-packages/theano/compile/debugmode.py", line 1809, in make_all
no_recycling)
File "/usr/local/lib/python2.7/dist-packages/theano/scan_module/scan_op.py", line 730, in make_thunk
self.validate_inner_graph()
File "/usr/local/lib/python2.7/dist-packages/theano/scan_module/scan_op.py", line 249, in validate_inner_graph
(self.name, type_input, type_output))
TypeError: Inconsistency in the inner graph of scan 'scan_fn' : an input and an output are associated with the same recurrent state and should have the same type but have type 'TensorType(float64, col)' and 'TensorType(float64, matrix)' respectively. 我已经做了一个星期的所有调试，但找不到问题。我怀疑 theano.scan 中的 outputs_info 的初始化是问题，但是当我删除第二维 (1) 时，即使在到达 f_pred_prob 函数（靠近 lstm_result ）。我不确定问题出在哪里。
通过将数据文件与 python 源文件放在同一目录中简单地执行该程序可以重现此问题。
请帮帮我。
感谢和问候， 无忧无虑
【问题讨论】：
标签： python machine-learning theano deep-learning theano.scan