RNN regression using Tensorflow? - python-2.7

Question

I am currently trying to implement a RNN for regression.
I need to create a neural network capable of converting audio samples into vector of mfcc feature. I've already know what the feature for each audio samples is, so the task it self is to create a neural network that is capable of converting a list of audio samples in to the desired MFCC feature.
The second problem I am facing is that since the audio files I am sampling has different length, will the list with the audio sample also have different length, which would cause problem with the number of input I need to feed into to the neural network. I found this post on how to handle variable sequence length, and tried to incorporate into my implementation of a RNN, but seem to not be able to get a lot of errors for unexplainable reasons..
Could anyone see what is going wrong with my implementation?
Here is the code:
def length(sequence): ##Zero padding to fit the max lenght... Question whether that is a good idea.
used = tf.sign(tf.reduce_max(tf.abs(sequence), reduction_indices=2))
length = tf.reduce_sum(used, reduction_indices=1)
length = tf.cast(length, tf.int32)
return length
def cost(output, target):
# Compute cross entropy for each frame.
cross_entropy = target * tf.log(output)
cross_entropy = -tf.reduce_sum(cross_entropy, reduction_indices=2)
mask = tf.sign(tf.reduce_max(tf.abs(target), reduction_indices=2))
cross_entropy *= mask
# Average over actual sequence lengths.
cross_entropy = tf.reduce_sum(cross_entropy, reduction_indices=1)
cross_entropy /= tf.reduce_sum(mask, reduction_indices=1)
return tf.reduce_mean(cross_entropy)
def last_relevant(output):
max_length = int(output.get_shape()[1])
relevant = tf.reduce_sum(tf.mul(output, tf.expand_dims(tf.one_hot(length, max_length), -1)), 1)
return relevant
files_train_path = [dnn_train+f for f in listdir(dnn_train) if isfile(join(dnn_train, f))]
files_test_path = [dnn_test+f for f in listdir(dnn_test) if isfile(join(dnn_test, f))]
files_train_name = [f for f in listdir(dnn_train) if isfile(join(dnn_train, f))]
files_test_name = [f for f in listdir(dnn_test) if isfile(join(dnn_test, f))]
os.chdir(dnn_train)
train_name,train_data = generate_list_of_names_data(files_train_path)
train_data, train_names, train_output_data, train_class_output = load_sound_files(files_train_path,train_name,train_data)
max_length = 0 ## Used for variable sequence input
for element in train_data:
if element.size > max_length:
max_length = element.size
NUM_EXAMPLES = len(train_data)/2
test_data = train_data[NUM_EXAMPLES:]
test_output = train_output_data[NUM_EXAMPLES:]
train_data = train_data[:NUM_EXAMPLES]
train_output = train_output_data[:NUM_EXAMPLES]
print("--- %s seconds ---" % (time.time() - start_time))
#----------------------------------------------------------------------#
#----------------------------Main--------------------------------------#
### Tensorflow neural network setup
batch_size = None
sequence_length_max = max_length
input_dimension=1
data = tf.placeholder(tf.float32,[batch_size,sequence_length_max,input_dimension])
target = tf.placeholder(tf.float32,[None,14])
num_hidden = 24 ## Hidden layer
cell = tf.nn.rnn_cell.LSTMCell(num_hidden,state_is_tuple=True) ## Long short term memory
output, state = tf.nn.dynamic_rnn(cell, data, dtype=tf.float32,sequence_length = length(data)) ## Creates the Rnn skeleton
last = last_relevant(output)#tf.gather(val, int(val.get_shape()[0]) - 1) ## Appedning as last
weight = tf.Variable(tf.truncated_normal([num_hidden, int(target.get_shape()[1])]))
bias = tf.Variable(tf.constant(0.1, shape=[target.get_shape()[1]]))
prediction = tf.nn.softmax(tf.matmul(last, weight) + bias)
cross_entropy = cost(output,target)# How far am I from correct value?
optimizer = tf.train.AdamOptimizer() ## TensorflowOptimizer
minimize = optimizer.minimize(cross_entropy)
mistakes = tf.not_equal(tf.argmax(target, 1), tf.argmax(prediction, 1))
error = tf.reduce_mean(tf.cast(mistakes, tf.float32))
## Training ##
init_op = tf.initialize_all_variables()
sess = tf.Session()
sess.run(init_op)
batch_size = 1000
no_of_batches = int(len(train_data)/batch_size)
epoch = 5000
for i in range(epoch):
ptr = 0
for j in range(no_of_batches):
inp, out = train_data[ptr:ptr+batch_size], train_output[ptr:ptr+batch_size]
ptr+=batch_size
sess.run(minimize,{data: inp, target: out})
print "Epoch - ",str(i)
incorrect = sess.run(error,{data: test_data, target: test_output})
print('Epoch {:2d} error {:3.1f}%'.format(i + 1, 100 * incorrect))
sess.close()
Error message:
Traceback (most recent call last):
File "tensorflow_test.py", line 177, in <module>
last = last_relevant(output)#tf.gather(val, int(val.get_shape()[0]) - 1) ## Appedning as last
File "tensorflow_test.py", line 132, in last_relevant
relevant = tf.reduce_sum(tf.mul(output, tf.expand_dims(tf.one_hot(length, max_length), -1)), 1)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/ops/array_ops.py", line 2778, in one_hot
name)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/ops/gen_array_ops.py", line 1413, in _one_hot
axis=axis, name=name)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/framework/op_def_library.py", line 454, in apply_op
as_ref=input_arg.is_ref)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/framework/ops.py", line 621, in convert_to_tensor
ret = conversion_func(value, dtype=dtype, name=name, as_ref=as_ref)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/framework/constant_op.py", line 180, in _constant_tensor_conversion_function
return constant(v, dtype=dtype, name=name)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/framework/constant_op.py", line 163, in constant
tensor_util.make_tensor_proto(value, dtype=dtype, shape=shape))
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/framework/tensor_util.py", line 421, in make_tensor_proto
tensor_proto.string_val.extend([compat.as_bytes(x) for x in proto_values])
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/util/compat.py", line 45, in as_bytes
(bytes_or_text,))
TypeError: Expected binary or unicode string, got <function length at 0x7f51a7a3ede8>
Edit:
Changing the tf.one_hot(lenght(output),max_length) gives me this error message:
Traceback (most recent call last):
File "tensorflow_test.py", line 184, in <module>
cross_entropy = cost(output,target)# How far am I from correct value?
File "tensorflow_test.py", line 121, in cost
cross_entropy = target * tf.log(output)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/ops/math_ops.py", line 754, in binary_op_wrapper
return func(x, y, name=name)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/ops/math_ops.py", line 903, in _mul_dispatch
return gen_math_ops.mul(x, y, name=name)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/ops/gen_math_ops.py", line 1427, in mul
result = _op_def_lib.apply_op("Mul", x=x, y=y, name=name)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/framework/op_def_library.py", line 703, in apply_op
op_def=op_def)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/framework/ops.py", line 2312, in create_op
set_shapes_for_outputs(ret)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/framework/ops.py", line 1704, in set_shapes_for_outputs
shapes = shape_func(op)
File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/ops/math_ops.py", line 1801, in _BroadcastShape
% (shape_x, shape_y))
ValueError: Incompatible shapes for broadcasting: (?, 14) and (?, 138915, 24)

Answer 1

tf.one_hot(length, ...)
here length is a function, not a tensor. Try length(something) instead.