def set_swish(self, memory_efficient=True):
"""Sets swish function as memory efficient (for training) or standard (for export).
Args:
memory_efficient (bool): Whether to use memory-efficient version of swish.
"""
self._swish = MemoryEfficientSwish() if memory_efficient else Swish()
for block in self.layers:
block.set_swish(memory_efficient)
def __init__(self, layer=[1, 2, 2, 3, 3, 4]):
super().__init__()
blocks_args, global_params = get_model_params('efficientnet-b6', None)
assert isinstance(blocks_args, list), 'blocks_args should be a list'
assert len(blocks_args) > 0, 'block args must be greater than 0'
self._global_params = global_params
self._blocks_args = blocks_args
# Batch norm parameters
bn_mom = 1 - self._global_params.batch_norm_momentum
bn_eps = self._global_params.batch_norm_epsilon
# Get stem static or dynamic convolution depending on image size
image_size = global_params.image_size
Conv2d = get_same_padding_conv2d(image_size=image_size)
# Stem
in_channels = 3 # rgb
out_channels = round_filters(
32, self._global_params) # number of output channels
self._conv_stem = Conv2d(in_channels,
out_channels,
kernel_size=3,
stride=2,
bias=False)
self._bn0 = nn.BatchNorm2d(num_features=out_channels,
momentum=bn_mom,
eps=bn_eps)
image_size = calculate_output_image_size(image_size, 2)
# Build blocks
self.channels = []
self.layers = nn.ModuleList([])
for block_args in self._blocks_args:
# Update block input and output filters based on depth multiplier.
block_args = block_args._replace(
input_filters=round_filters(block_args.input_filters,
self._global_params),
output_filters=round_filters(block_args.output_filters,
self._global_params),
num_repeat=round_repeats(block_args.num_repeat,
self._global_params))
self.channels += [block_args.output_filters
] * block_args.num_repeat
# The first block needs to take care of stride and filter size increase.
self.layers.append(
MBConvBlock(block_args,
self._global_params,
image_size=image_size))
image_size = calculate_output_image_size(image_size,
block_args.stride)
if block_args.num_repeat > 1: # modify block_args to keep same output size
block_args = block_args._replace(
input_filters=block_args.output_filters, stride=1)
for _ in range(block_args.num_repeat - 1):
self.layers.append(
MBConvBlock(block_args,
self._global_params,
image_size=image_size))
# image_size = calculate_output_image_size(image_size, block_args.stride) # stride = 1
self._swish = MemoryEfficientSwish()
self.backbone_modules = [
m for m in self.modules() if isinstance(m, nn.Conv2d)
]
def __init__(self, block_args, global_params, image_size=None):
super().__init__()
self._block_args = block_args
self._bn_mom = 1 - global_params.batch_norm_momentum # pytorch's difference from tensorflow
self._bn_eps = global_params.batch_norm_epsilon
self.has_se = (self._block_args.se_ratio
is not None) and (0 < self._block_args.se_ratio <= 1)
self.id_skip = block_args.id_skip # whether to use skip connection and drop connect
# Expansion phase (Inverted Bottleneck)
inp = self._block_args.input_filters # number of input channels
oup = self._block_args.input_filters * self._block_args.expand_ratio # number of output channels
if self._block_args.expand_ratio != 1:
Conv2d = get_same_padding_conv2d(image_size=image_size)
self._expand_conv = Conv2d(in_channels=inp,
out_channels=oup,
kernel_size=1,
bias=False)
self._bn0 = nn.BatchNorm2d(num_features=oup,
momentum=self._bn_mom,
eps=self._bn_eps)
# image_size = calculate_output_image_size(image_size, 1) <-- this wouldn't modify image_size
# Depthwise convolution phase
k = self._block_args.kernel_size
s = self._block_args.stride
Conv2d = get_same_padding_conv2d(image_size=image_size)
self._depthwise_conv = Conv2d(
in_channels=oup,
out_channels=oup,
groups=oup, # groups makes it depthwise
kernel_size=k,
stride=s,
bias=False)
self._bn1 = nn.BatchNorm2d(num_features=oup,
momentum=self._bn_mom,
eps=self._bn_eps)
image_size = calculate_output_image_size(image_size, s)
# Squeeze and Excitation layer, if desired
if self.has_se:
Conv2d = get_same_padding_conv2d(image_size=(1, 1))
num_squeezed_channels = max(
1,
int(self._block_args.input_filters *
self._block_args.se_ratio))
self._se_reduce = Conv2d(in_channels=oup,
out_channels=num_squeezed_channels,
kernel_size=1)
self._se_expand = Conv2d(in_channels=num_squeezed_channels,
out_channels=oup,
kernel_size=1)
# Pointwise convolution phase
final_oup = self._block_args.output_filters
Conv2d = get_same_padding_conv2d(image_size=image_size)
self._project_conv = Conv2d(in_channels=oup,
out_channels=final_oup,
kernel_size=1,
bias=False)
self._bn2 = nn.BatchNorm2d(num_features=final_oup,
momentum=self._bn_mom,
eps=self._bn_eps)
self._swish = MemoryEfficientSwish()