def conv1d_sd(input, filters, image_shape, filter_shape, border_mode='valid',
subsample=(1,), filter_flip=True):
"""
using a single dot product
"""
if border_mode not in ('valid', 0, (0,)):
raise RuntimeError("Unsupported border_mode for conv1d_sd: "
"%s" % border_mode)
batch_size, num_input_channels, input_length = image_shape
num_filters, num_input_channels_, filter_length = filter_shape
stride = subsample[0]
if filter_length % stride > 0:
raise RuntimeError("Filter length (%d) is not a multiple of the "
"stride (%d)" % (filter_length, stride))
num_steps = filter_length // stride
output_length = (input_length - filter_length + stride) // stride
# pad the input so all the shifted dot products fit inside.
# shape is (b, c, l)
padded_length = ((input_length // filter_length) * filter_length +
(num_steps - 1) * stride)
# at this point, it is possible that the padded_length is SMALLER than the
# input size. so then we have to truncate first.
truncated_length = min(input_length, padded_length)
input_truncated = input[:, :, :truncated_length]
input_padded_shape = (batch_size, num_input_channels, padded_length)
input_padded = T.zeros(input_padded_shape)
input_padded = T.set_subtensor(input_padded[:, :, :truncated_length],
input_truncated)
inputs = []
for num in range(num_steps):
shift = num * stride
length = (padded_length - shift) // filter_length
r_input_shape = (batch_size, num_input_channels, length, filter_length)
r_input = input_padded[
:, :, shift:length * filter_length + shift].reshape(r_input_shape)
inputs.append(r_input)
inputs_stacked = T.stack(*inputs) # shape is (n, b, c, w, f)
filters_flipped = filters[:, :, ::-1] if filter_flip else filters
r_conved = T.tensordot(inputs_stacked, filters_flipped,
np.asarray([[2, 4], [1, 2]]))
# resulting shape is (n, b, w, n_filters)
# output needs to be (b, n_filters, w * n)
r_conved = r_conved.dimshuffle(1, 3, 2, 0) # (b, n_filters, w, n)
conved = r_conved.reshape((r_conved.shape[0], r_conved.shape[1],
r_conved.shape[2] * r_conved.shape[3]))
# result is (b, n_f, l)
# remove padding
return conved[:, :, :output_length]
def conv1d_md(input, filters, image_shape, filter_shape, border_mode='valid',
subsample=(1,), filter_flip=True):
"""
using multiple dot products
"""
if border_mode not in ('valid', 0, (0,)):
raise RuntimeError("Unsupported border_mode for conv1d_md: "
"%s" % border_mode)
batch_size, num_input_channels, input_length = image_shape
num_filters, num_input_channels_, filter_length = filter_shape
stride = subsample[0]
if filter_length % stride > 0:
raise RuntimeError("Filter length (%d) is not a multiple of the "
"stride (%d)" % (filter_length, stride))
num_steps = filter_length // stride
output_length = (input_length - filter_length + stride) // stride
output_shape = (batch_size, num_filters, output_length)
filters_flipped = filters[:, :, ::-1] if filter_flip else filters
conved = T.zeros(output_shape)
for num in range(num_steps):
shift = num * stride
length = (input_length - shift) // filter_length
if length == 0:
# we can safely skip this product, it doesn't contribute to the
# final convolution.
continue
r_input_shape = (batch_size, num_input_channels, length, filter_length)
r_input = input[
:, :, shift:length * filter_length + shift].reshape(r_input_shape)
# shape (b, l, n_filters)
r_conved = T.tensordot(r_input, filters_flipped,
np.asarray([[1, 3], [1, 2]]))
r_conved = r_conved.dimshuffle(0, 2, 1) # shape is (b, n_filters, l)
conved = T.set_subtensor(conved[:, :, num::num_steps], r_conved)
return conved