def apply(self, x, nout, strides=(1, 1), bottleneck=True):
features = nout
nout = nout * 4 if bottleneck else nout
needs_projection = x.shape[-1] != nout or strides != (1, 1)
residual = x
if needs_projection:
residual = StdConv(residual,
nout, (1, 1),
strides,
bias=False,
name="conv_proj")
residual = nn.GroupNorm(residual, epsilon=1e-4, name="gn_proj")
if bottleneck:
x = StdConv(x, features, (1, 1), bias=False, name="conv1")
x = nn.GroupNorm(x, epsilon=1e-4, name="gn1")
x = nn.relu(x)
x = StdConv(x, features, (3, 3), strides, bias=False, name="conv2")
x = nn.GroupNorm(x, epsilon=1e-4, name="gn2")
x = nn.relu(x)
last_kernel = (1, 1) if bottleneck else (3, 3)
x = StdConv(x, nout, last_kernel, bias=False, name="conv3")
x = nn.GroupNorm(x,
epsilon=1e-4,
name="gn3",
scale_init=nn.initializers.zeros)
x = nn.relu(residual + x)
return x
def apply(self, x, nout, strides=(1, 1)):
needs_projection = x.shape[-1] != nout * 4 or strides != (1, 1)
residual = x
if needs_projection:
residual = StdConv(residual,
nout * 4, (1, 1),
strides,
bias=False,
name='conv_proj')
residual = nn.GroupNorm(residual, name='gn_proj')
y = StdConv(x, nout, (1, 1), bias=False, name='conv1')
y = nn.GroupNorm(y, name='gn1')
y = nn.relu(y)
y = StdConv(y, nout, (3, 3), strides, bias=False, name='conv2')
y = nn.GroupNorm(y, name='gn2')
y = nn.relu(y)
y = StdConv(y, nout * 4, (1, 1), bias=False, name='conv3')
y = nn.GroupNorm(y, name='gn3', scale_init=nn.initializers.zeros)
y = nn.relu(residual + y)
return y
def apply(self,
x,
num_classes=1000,
train=False,
width_factor=1,
num_layers=50):
del train
blocks, bottleneck = get_block_desc(num_layers)
width = int(64 * width_factor)
# Root block
x = StdConv(x, width, (7, 7), (2, 2), bias=False, name="conv_root")
x = nn.GroupNorm(x, name="gn_root")
x = nn.relu(x)
x = nn.max_pool(x, (3, 3), strides=(2, 2), padding="SAME")
# Stages
x = ResNetStage(x,
blocks[0],
width,
first_stride=(1, 1),
bottleneck=bottleneck,
name="block1")
for i, block_size in enumerate(blocks[1:], 1):
x = ResNetStage(x,
block_size,
width * 2**i,
first_stride=(2, 2),
bottleneck=bottleneck,
name=f"block{i + 1}")
# Head
x = jnp.mean(x, axis=(1, 2))
x = IdentityLayer(x, name="pre_logits")
x = nn.Dense(x,
num_classes,
kernel_init=nn.initializers.zeros,
name="head")
return x
def apply(self,
x,
num_classes=1000,
train=False,
resnet=None,
patches=None,
hidden_size=None,
transformer=None,
representation_size=None,
classifier='gap'):
# (Possibly partial) ResNet root.
if resnet is not None:
width = int(64 * resnet.width_factor)
# Root block.
x = models_resnet.StdConv(x,
width, (7, 7), (2, 2),
bias=False,
name='conv_root')
x = nn.GroupNorm(x, name='gn_root')
x = nn.relu(x)
x = nn.max_pool(x, (3, 3), strides=(2, 2), padding='SAME')
# ResNet stages.
x = models_resnet.ResNetStage(x,
resnet.num_layers[0],
width,
first_stride=(1, 1),
name='block1')
for i, block_size in enumerate(resnet.num_layers[1:], 1):
x = models_resnet.ResNetStage(x,
block_size,
width * 2**i,
first_stride=(2, 2),
name=f'block{i + 1}')
n, h, w, c = x.shape
# We can merge s2d+emb into a single conv; it's the same.
x = nn.Conv(x,
hidden_size,
patches.size,
strides=patches.size,
padding='VALID',
name='embedding')
# Here, x is a grid of embeddings.
# (Possibly partial) Transformer.
if transformer is not None:
n, h, w, c = x.shape
x = jnp.reshape(x, [n, h * w, c])
# If we want to add a class token, add it here.
if classifier == 'token':
cls = self.param('cls', (1, 1, c), nn.initializers.zeros)
cls = jnp.tile(cls, [n, 1, 1])
x = jnp.concatenate([cls, x], axis=1)
x = Encoder(x, train=train, name='Transformer', **transformer)
if classifier == 'token':
x = x[:, 0]
elif classifier == 'gap':
x = jnp.mean(x, axis=list(range(1, x.ndim - 1))) # (1,) or (1,2)
if representation_size is not None:
x = nn.Dense(x, representation_size, name='pre_logits')
x = nn.tanh(x)
else:
x = IdentityLayer(x, name='pre_logits')
x = nn.Dense(x,
num_classes,
name='head',
kernel_init=nn.initializers.zeros)
return x
def apply(self,
x,
num_classes=1,
train=False,
hidden_size=None,
transformer=None,
resnet_emb=None,
representation_size=None):
"""Apply model on inputs.
Args:
x: the processed input patches and position annotations.
num_classes: the number of output classes. 1 for single model.
train: train or eval.
hidden_size: the hidden dimension for patch embedding tokens.
transformer: the model config for Transformer backbone.
resnet_emb: the config for patch embedding w/ small resnet.
representation_size: size of the last FC before prediction.
Returns:
Model prediction output.
"""
assert transformer is not None
# Either 3: (batch size, seq len, channel) or
# 4: (batch size, crops, seq len, channel)
assert len(x.shape) in [3, 4]
multi_crops_input = False
if len(x.shape) == 4:
multi_crops_input = True
batch_size, num_crops, l, channel = x.shape
x = jnp.reshape(x, [batch_size * num_crops, l, channel])
# We concat (x, spatial_positions, scale_posiitons, input_masks)
# when preprocessing.
inputs_spatial_positions = x[:, :, -3]
inputs_spatial_positions = inputs_spatial_positions.astype(jnp.int32)
inputs_scale_positions = x[:, :, -2]
inputs_scale_positions = inputs_scale_positions.astype(jnp.int32)
inputs_masks = x[:, :, -1]
inputs_masks = inputs_masks.astype(jnp.bool_)
x = x[:, :, :-3]
n, l, channel = x.shape
if hidden_size:
if resnet_emb:
# channel = patch_size * patch_size * 3
patch_size = int(np.sqrt(channel // 3))
x = jnp.reshape(x, [-1, patch_size, patch_size, 3])
x = resnet.StdConv(
x, RESNET_TOKEN_DIM, (7, 7), (2, 2), bias=False, name="conv_root")
x = nn.GroupNorm(x, name="gn_root")
x = nn.relu(x)
x = nn.max_pool(x, (3, 3), strides=(2, 2), padding="SAME")
if resnet_emb.num_layers > 0:
blocks, bottleneck = resnet.get_block_desc(resnet_emb.num_layers)
if blocks:
x = resnet.ResNetStage(
x,
blocks[0],
RESNET_TOKEN_DIM,
first_stride=(1, 1),
bottleneck=bottleneck,
name="block1")
for i, block_size in enumerate(blocks[1:], 1):
x = resnet.ResNetStage(
x,
block_size,
RESNET_TOKEN_DIM * 2**i,
first_stride=(2, 2),
bottleneck=bottleneck,
name=f"block{i + 1}")
x = jnp.reshape(x, [n, l, -1])
x = nn.Dense(x, hidden_size, name="embedding")
# Here, x is a list of embeddings.
x = utils.Encoder(
x,
inputs_spatial_positions,
inputs_scale_positions,
inputs_masks,
train=train,
name="Transformer",
**transformer)
x = x[:, 0]
if representation_size:
x = nn.Dense(x, representation_size, name="pre_logits")
x = nn.tanh(x)
else:
x = resnet.IdentityLayer(x, name="pre_logits")
x = nn.Dense(x, num_classes, name="head", kernel_init=nn.initializers.zeros)
if multi_crops_input:
_, channel = x.shape
x = jnp.reshape(x, [batch_size, num_crops, channel])
return x
