def _prepare_component_wise_processing(self,
w_tensor,
latent_indicators_tensor,
*input_tensors,
zero_prob_val=0.0):
indices, values = self._combine_values_and_indices(input_tensors)
# Create a 3D tensor with dimensions [batch, sum node, sum input]
# The last axis will have zeros when the sum size is less than the max sum size
if all(np.array_equal(indices[0], ind) for ind in indices):
# In case all sum nodes model the same sum, we can just use broadcasting
reducible_values = tf.reshape(
tf.gather(values, indices[0], axis=1),
(-1, 1, self._max_sum_size))
elif len(set(self._sum_sizes)) == 1:
# In case all sum sizes are the same, use gather and reshape accordingly
indices_flat = list(itertools.chain(*indices))
reducible_values = tf.reshape(
tf.gather(values, indices_flat, axis=1),
(-1, self._num_sums, self._max_sum_size))
else:
reducible_values = utils.gather_cols_3d(values,
indices,
pad_elem=zero_prob_val,
name="GatherToReducible")
w_tensor = tf.expand_dims(w_tensor, axis=self._batch_axis)
if latent_indicators_tensor is not None:
latent_indicators_tensor = tf.reshape(latent_indicators_tensor,
shape=(-1, self._num_sums,
self._max_sum_size))
return w_tensor, latent_indicators_tensor, reducible_values
def _compute_log_mpe_path(self, counts, *value_values, add_random=False,
use_unweighted=False, sample=False, sample_prob=None):
# Path per product node is calculated by permuting backwards to the
# input nodes, then adding the appropriate counts per input, and then
# scattering the summed counts to value inputs
# Check inputs
if not self._values:
raise StructureError("%s is missing input values." % self)
def permute_counts(input_sizes):
# Function that permutes count values, backward to inputs.
counts_indices_list = []
def range_with_blocksize(start, stop, block_size, step):
# A function that produces an arithmetic progression (Similar to
# Python's range() function), but for a given block-size of
# consecutive numbers.
# E.g: range_with_blocksize(start=0, stop=20, block_size=3, step=5)
# = [0, 1, 2, 5, 6, 7, 10, 11, 12, 15, 16, 17]
counts_indices = []
it = 0
low = start
high = low + block_size
while low < stop:
counts_indices = counts_indices + list(range(low, high))
it += 1
low = start + (it * step)
high = low + block_size
return counts_indices
for inp, inp_size in enumerate(input_sizes):
block_size = int(self._num_prods / np.prod(input_sizes[:inp+1]))
step = int(np.prod(input_sizes[inp:]))
for i in range(inp_size):
start = i * block_size
stop = self._num_prods - (block_size * (inp_size-i-1))
counts_indices_list.append(range_with_blocksize(start, stop,
block_size,
step))
return counts_indices_list
if (len(self._input_sizes) > 1):
permuted_indices = permute_counts(self._input_sizes)
summed_counts = tf.reduce_sum(utils.gather_cols_3d(counts, permuted_indices),
axis=-1)
processed_counts_list = tf.split(summed_counts, self._input_sizes, axis=-1)
else: # For single input case, i.e, when _num_prods = 1
summed_counts = self._input_sizes[0] * [counts]
processed_counts_list = [tf.concat(values=summed_counts, axis=-1)]
# Zip lists of processed counts and value_values together for scattering
value_counts = zip(processed_counts_list, value_values)
return self._scatter_to_input_tensors(*value_counts)
def _compute_log_mpe_path(self, counts, *value_values,
use_unweighted=False, sample=False, sample_prob=None):
# Check inputs
if not self._values:
raise StructureError("%s is missing input values." % self)
# For each unique (input, index) pair in the values list, collect counts
# index of all counts for which the pair is a child of
gather_counts_indices, unique_inputs = self._collect_count_indices_per_input()
if self._num_prods > 1:
# Gather columns from the counts tensor, per unique (input, index) pair
reducible_values = utils.gather_cols_3d(counts, gather_counts_indices)
# Sum gathered counts together per unique (input, index) pair
summed_counts = tf.reduce_sum(reducible_values, axis=-1)
else:
# Calculate total inputs size
inputs_size = sum([v_input.get_size(v_value) for v_input, v_value in
zip(self._values, value_values)])
# Tile counts only if input is larger than 1
summed_counts = (tf.tile(counts, [1, inputs_size]) if inputs_size > 1
else counts)
# For each unique input in the values list, calculate the number of
# unique indices
unique_inp_sizes = [len(v) for v in unique_inputs.values()]
# Split the summed-counts tensor per unique input, based on input-sizes
unique_input_counts = tf.split(summed_counts, unique_inp_sizes, axis=-1) \
if len(unique_inp_sizes) > 1 else [summed_counts]
# Scatter each unique-counts tensor to the respective input, only once
# per unique input in the values list
scattered_counts = [None] * len(self._values)
for (node, inds), cnts in zip(unique_inputs.items(), unique_input_counts):
for i, (inp, val) in enumerate(zip(self._values, value_values)):
if inp.node == node:
scattered_counts[i] = utils.scatter_cols(
cnts, inds, int(val.get_shape()[0 if val.get_shape().ndims
== 1 else 1]))
break
return scattered_counts
def _compute_value_common(self, *value_tensors, padding_value=0.0):
"""Common actions when computing value."""
# Check inputs
if not self._values:
raise StructureError("%s is missing input values." % self)
# Prepare values
if self._num_prods > 1:
indices, value_tensor = self._combine_values_and_indices(value_tensors)
# Create a 3D tensor with dimensions [batch, num-prods, max-prod-input-sizes]
# The last axis will have zeros or ones (for log or non-log) when the
# prod-input-size < max-prod-input-sizes
reducible_values = utils.gather_cols_3d(value_tensor, indices,
pad_elem=padding_value)
return reducible_values
else:
# Gather input tensors
value_tensors = self._gather_input_tensors(*value_tensors)
return tf.concat(value_tensors, 1)
def _accumulate_uniq_values_and_split(self,
flat_col_indices,
flat_tensor_offsets,
x,
unique_tensors_offsets_dict,
gather_segments_only=False):
"""Helper method that is used for summing counts within the layer before passing it on
by means of gathering from the (padded) weighted values and reducing afterwards.
Args:
flat_col_indices (numpy.ndarray): An array containing the flattened column indices to
gather from the concatenation of unqiue value tensors.
flat_tensor_offsets (numpy.ndarray): An array containing the flattened tensor offsets
in the concatenation of the unique value tensors.
x (Tensor): A ``Tensor`` to gather, accumulate per unique value tensor and finally
split for scattering.
unique_tensors_offsets_dict (OrderedDict): A mapping of ``Tensor`` -> offset
corresponding to the unique value tensors and their offsets in the concatenation.
gather_segments_only (bool): If ``True``, will transpose and gather on the zeroth
axis, without 'zero-probability' padding so that the result can be accumulated
using tf.segment_sum.
Returns:
A list of indices to be used for scattering the values of the list in the second
return value, which is a list of accumulated values corresponding to the unique
value Inputs of this node.
"""
# Make a flat list containing the sum index for each of the 'concatenated' inputs
sum_indices = []
for i, size in enumerate(self._sum_sizes):
sum_indices.extend([i for _ in range(size)])
# For each unique tensor and index pair, we should have a list of indices to gather from
# the reducible values tensor
max_size = max(self._sum_sizes)
unique_tensor_gather_indices = OrderedDict()
unique_tensors_offsets_inverse = {
v: k
for k, v in unique_tensors_offsets_dict.items()
}
old_sum_index = 0
start_of_current_sum = 0
for i, (col, tensor_offset, sum_index) in enumerate(
zip(flat_col_indices, flat_tensor_offsets, sum_indices)):
# Give the offset of the current flat (axis 1) index, we get the input tensor that
# feeds its value to it.
tensor = unique_tensors_offsets_inverse[tensor_offset]
if tensor not in unique_tensor_gather_indices:
unique_tensor_gather_indices[tensor] = defaultdict(list)
# For this tensor-column combination, we register the corresponding index to gather
# from the padded 2D reducible tensor
if sum_index != old_sum_index:
old_sum_index = sum_index
start_of_current_sum = i
# Index of the column within the sum
index_within_sum = i - start_of_current_sum
# Given the index of the sum and the index of the column within, we can find the index
# to gather for this particular column of the input tensor
unique_tensor_gather_indices[tensor][col].append(index_within_sum +
sum_index *
max_size)
# For each tensor that we have, we compute the scatter indices. Here we construct the
# nested gather indices needed for gather_cols_3d.
nested_gather_indices = []
unique_tensor_lengths = []
tensor_scatter_indices = OrderedDict()
for tensor, col_to_gather_col in unique_tensor_gather_indices.items():
gather_indices_sub = []
tensor_scatter_indices[tensor] = []
# Go over all possible indices
for i in range(tensor.shape[1].value):
# If this index is registered as one to gather for...
if i in col_to_gather_col:
# ... then we append the gathering columns to the currently considered
# tensor column
gather_indices_sub.append(col_to_gather_col[i])
tensor_scatter_indices[tensor].append(i)
# Length of the list of columns for each unique input value tensor
unique_tensor_lengths.append(len(gather_indices_sub))
# Will contain a list of lists. Inner lists correspond to columns to gather, while
# outer list corresponds to the individual 'indexed' input nodes
nested_gather_indices.extend(gather_indices_sub)
# Gather columns from the counts tensor, per unique (input, index) pair
if gather_segments_only:
segment_ids = []
for i, ind in enumerate(nested_gather_indices):
segment_ids.extend([i for _ in range(len(ind))])
num_sums_to_scatter = len(nested_gather_indices)
nested_gather_indices = list(
itertools.chain(*nested_gather_indices))
transposed = tf.transpose(x)
gathered = tf.gather(transposed, indices=nested_gather_indices)
acccumulated = tf.reshape(
tf.segment_sum(gathered, segment_ids=segment_ids),
(num_sums_to_scatter, -1))
acccumulated = tf.transpose(acccumulated)
else:
reducible_values = utils.gather_cols_3d(x, nested_gather_indices)
# Sum gathered counts together per unique (input, index) pair
acccumulated = tf.reduce_sum(reducible_values, axis=-1)
# Split the summed-counts tensor per unique input, based on input-sizes
accumulated_unique_tensor_values = tf.split(
acccumulated, unique_tensor_lengths, axis=-1) \
if len(unique_tensor_lengths) > 1 else [acccumulated]
return tensor_scatter_indices, accumulated_unique_tensor_values
