def MakeMain(input_shape):
# the number of output channels depends on the number of input channels
return stax.serial(stax.Conv(filters1, (1, 1)), stax.BatchNorm(),
stax.Relu,
stax.Conv(filters2, (ks, ks), padding='SAME'),
stax.BatchNorm(), stax.Relu,
stax.Conv(input_shape[3], (1, 1)), stax.BatchNorm())
def WideResnetBlock(channels, strides=(1, 1), channel_mismatch=False):
"""WideResnet convolutational block."""
main = stax.Serial(stax.BatchNorm(), stax.Relu(),
stax.Conv(channels, (3, 3), strides, padding='SAME'),
stax.BatchNorm(), stax.Relu(),
stax.Conv(channels, (3, 3), padding='SAME'))
shortcut = stax.Identity() if not channel_mismatch else stax.Conv(
channels, (3, 3), strides, padding='SAME')
return stax.Serial(stax.FanOut(), stax.Parallel(main, shortcut),
stax.FanInSum())
def IdentityBlock(kernel_size, filters):
"""ResNet identical size block."""
ks = kernel_size
filters1, filters2, filters3 = filters
main = stax.Serial(stax.Conv(filters1, (1, 1)), stax.BatchNorm(),
stax.Relu(),
stax.Conv(filters2, (ks, ks), padding='SAME'),
stax.BatchNorm(), stax.Relu(),
stax.Conv(filters3, (1, 1)), stax.BatchNorm())
return stax.Serial(stax.FanOut(), stax.Parallel(main, stax.Identity()),
stax.FanInSum(), stax.Relu())
def ConvBlock(kernel_size, filters, strides):
"""ResNet convolutional striding block."""
ks = kernel_size
filters1, filters2, filters3 = filters
main = stax.Serial(stax.Conv(filters1, (1, 1), strides), stax.BatchNorm(),
stax.Relu(),
stax.Conv(filters2, (ks, ks), padding='SAME'),
stax.BatchNorm(), stax.Relu(),
stax.Conv(filters3, (1, 1)), stax.BatchNorm())
shortcut = stax.Serial(stax.Conv(filters3, (1, 1), strides),
stax.BatchNorm())
return stax.Serial(stax.FanOut(), stax.Parallel(main, shortcut),
stax.FanInSum(), stax.Relu())
def Resnet50(hidden_size=64, num_output_classes=1001):
"""ResNet.
Args:
hidden_size: the size of the first hidden layer (multiplied later).
num_output_classes: how many classes to distinguish.
Returns:
The ResNet model with the given layer and output sizes.
"""
return stax.serial(
stax.Conv(hidden_size, (7, 7), (2, 2),
'SAME'), stax.BatchNorm(), stax.Relu,
stax.MaxPool((3, 3), strides=(2, 2)),
ConvBlock(3, [hidden_size, hidden_size, 4 * hidden_size], (1, 1)),
IdentityBlock(3, [hidden_size, hidden_size]),
IdentityBlock(3, [hidden_size, hidden_size]),
ConvBlock(3,
[2 * hidden_size, 2 * hidden_size, 8 * hidden_size], (2, 2)),
IdentityBlock(3, [2 * hidden_size, 2 * hidden_size]),
IdentityBlock(3, [2 * hidden_size, 2 * hidden_size]),
IdentityBlock(3, [2 * hidden_size, 2 * hidden_size]),
ConvBlock(3, [4 * hidden_size, 4 * hidden_size, 16 * hidden_size],
(2, 2)), IdentityBlock(3,
[4 * hidden_size, 4 * hidden_size]),
IdentityBlock(3, [4 * hidden_size, 4 * hidden_size]),
IdentityBlock(3, [4 * hidden_size, 4 * hidden_size]),
IdentityBlock(3, [4 * hidden_size, 4 * hidden_size]),
IdentityBlock(3, [4 * hidden_size, 4 * hidden_size]),
ConvBlock(3, [8 * hidden_size, 8 * hidden_size, 32 * hidden_size],
(2, 2)), IdentityBlock(3,
[8 * hidden_size, 8 * hidden_size]),
IdentityBlock(3, [8 * hidden_size, 8 * hidden_size]),
stax.AvgPool((7, 7)), stax.Flatten(), stax.Dense(num_output_classes),
stax.LogSoftmax)
def WideResnet(num_blocks=3, hidden_size=64, num_output_classes=10):
"""WideResnet from https://arxiv.org/pdf/1605.07146.pdf.
Args:
num_blocks: int, number of blocks in a group.
hidden_size: the size of the first hidden layer (multiplied later).
num_output_classes: int, number of classes to distinguish.
Returns:
The WideResnet model with given layer and output sizes.
"""
return stax.serial(stax.Conv(hidden_size, (3, 3), padding='SAME'),
WideResnetGroup(num_blocks, hidden_size),
WideResnetGroup(num_blocks, hidden_size * 2, (2, 2)),
WideResnetGroup(num_blocks, hidden_size * 4, (2, 2)),
stax.BatchNorm(), stax.Relu, stax.AvgPool((8, 8)),
stax.Flatten(), stax.Dense(num_output_classes),
stax.LogSoftmax)
def Resnet50(hidden_size=64, num_output_classes=1001, mode='train'):
"""ResNet.
Args:
hidden_size: the size of the first hidden layer (multiplied later).
num_output_classes: how many classes to distinguish.
mode: whether we are training or evaluating or doing inference.
Returns:
The ResNet model with the given layer and output sizes.
"""
del mode
return stax.Serial(
stax.Conv(hidden_size, (7, 7), (2, 2), 'SAME'), stax.BatchNorm(),
stax.Relu(), stax.MaxPool(pool_size=(3, 3), strides=(2, 2)),
ConvBlock(3, [hidden_size, hidden_size, 4 * hidden_size], (1, 1)),
IdentityBlock(3, [hidden_size, hidden_size, 4 * hidden_size]),
IdentityBlock(3, [hidden_size, hidden_size, 4 * hidden_size]),
ConvBlock(3, [2 * hidden_size, 2 * hidden_size, 8 * hidden_size],
(2, 2)),
IdentityBlock(3, [2 * hidden_size, 2 * hidden_size, 8 * hidden_size]),
IdentityBlock(3, [2 * hidden_size, 2 * hidden_size, 8 * hidden_size]),
IdentityBlock(3, [2 * hidden_size, 2 * hidden_size, 8 * hidden_size]),
ConvBlock(3, [4 * hidden_size, 4 * hidden_size, 16 * hidden_size],
(2, 2)),
IdentityBlock(3, [4 * hidden_size, 4 * hidden_size, 16 * hidden_size]),
IdentityBlock(3, [4 * hidden_size, 4 * hidden_size, 16 * hidden_size]),
IdentityBlock(3, [4 * hidden_size, 4 * hidden_size, 16 * hidden_size]),
IdentityBlock(3, [4 * hidden_size, 4 * hidden_size, 16 * hidden_size]),
IdentityBlock(3, [4 * hidden_size, 4 * hidden_size, 16 * hidden_size]),
ConvBlock(3, [8 * hidden_size, 8 * hidden_size, 32 * hidden_size],
(2, 2)),
IdentityBlock(3, [8 * hidden_size, 8 * hidden_size, 32 * hidden_size]),
IdentityBlock(3, [8 * hidden_size, 8 * hidden_size, 32 * hidden_size]),
stax.AvgPool(pool_size=(7, 7)), stax.Flatten(),
stax.Dense(num_output_classes), stax.LogSoftmax())