Source code for torchvision.ops.drop_block
import torch
import torch.fx
import torch.nn.functional as F
from torch import nn, Tensor
from ..utils import _log_api_usage_once
[docs]def drop_block2d(
input: Tensor, p: float, block_size: int, inplace: bool = False, eps: float = 1e-06, training: bool = True
) -> Tensor:
"""
Implements DropBlock2d from `"DropBlock: A regularization method for convolutional networks"
<https://arxiv.org/abs/1810.12890>`.
Args:
input (Tensor[N, C, H, W]): The input tensor or 4-dimensions with the first one
being its batch i.e. a batch with ``N`` rows.
p (float): Probability of an element to be dropped.
block_size (int): Size of the block to drop.
inplace (bool): If set to ``True``, will do this operation in-place. Default: ``False``.
eps (float): A value added to the denominator for numerical stability. Default: 1e-6.
training (bool): apply dropblock if is ``True``. Default: ``True``.
Returns:
Tensor[N, C, H, W]: The randomly zeroed tensor after dropblock.
"""
if not torch.jit.is_scripting() and not torch.jit.is_tracing():
_log_api_usage_once(drop_block2d)
if p < 0.0 or p > 1.0:
raise ValueError(f"drop probability has to be between 0 and 1, but got {p}.")
if input.ndim != 4:
raise ValueError(f"input should be 4 dimensional. Got {input.ndim} dimensions.")
if not training or p == 0.0:
return input
N, C, H, W = input.size()
block_size = min(block_size, W, H)
# compute the gamma of Bernoulli distribution
gamma = (p * H * W) / ((block_size**2) * ((H - block_size + 1) * (W - block_size + 1)))
noise = torch.empty((N, C, H - block_size + 1, W - block_size + 1), dtype=input.dtype, device=input.device)
noise.bernoulli_(gamma)
noise = F.pad(noise, [block_size // 2] * 4, value=0)
noise = F.max_pool2d(noise, stride=(1, 1), kernel_size=(block_size, block_size), padding=block_size // 2)
noise = 1 - noise
normalize_scale = noise.numel() / (eps + noise.sum())
if inplace:
input.mul_(noise).mul_(normalize_scale)
else:
input = input * noise * normalize_scale
return input
[docs]def drop_block3d(
input: Tensor, p: float, block_size: int, inplace: bool = False, eps: float = 1e-06, training: bool = True
) -> Tensor:
"""
Implements DropBlock3d from `"DropBlock: A regularization method for convolutional networks"
<https://arxiv.org/abs/1810.12890>`.
Args:
input (Tensor[N, C, D, H, W]): The input tensor or 5-dimensions with the first one
being its batch i.e. a batch with ``N`` rows.
p (float): Probability of an element to be dropped.
block_size (int): Size of the block to drop.
inplace (bool): If set to ``True``, will do this operation in-place. Default: ``False``.
eps (float): A value added to the denominator for numerical stability. Default: 1e-6.
training (bool): apply dropblock if is ``True``. Default: ``True``.
Returns:
Tensor[N, C, D, H, W]: The randomly zeroed tensor after dropblock.
"""
if not torch.jit.is_scripting() and not torch.jit.is_tracing():
_log_api_usage_once(drop_block3d)
if p < 0.0 or p > 1.0:
raise ValueError(f"drop probability has to be between 0 and 1, but got {p}.")
if input.ndim != 5:
raise ValueError(f"input should be 5 dimensional. Got {input.ndim} dimensions.")
if not training or p == 0.0:
return input
N, C, D, H, W = input.size()
block_size = min(block_size, D, H, W)
# compute the gamma of Bernoulli distribution
gamma = (p * D * H * W) / ((block_size**3) * ((D - block_size + 1) * (H - block_size + 1) * (W - block_size + 1)))
noise = torch.empty(
(N, C, D - block_size + 1, H - block_size + 1, W - block_size + 1), dtype=input.dtype, device=input.device
)
noise.bernoulli_(gamma)
noise = F.pad(noise, [block_size // 2] * 6, value=0)
noise = F.max_pool3d(
noise, stride=(1, 1, 1), kernel_size=(block_size, block_size, block_size), padding=block_size // 2
)
noise = 1 - noise
normalize_scale = noise.numel() / (eps + noise.sum())
if inplace:
input.mul_(noise).mul_(normalize_scale)
else:
input = input * noise * normalize_scale
return input
torch.fx.wrap("drop_block2d")
[docs]class DropBlock2d(nn.Module):
"""
See :func:`drop_block2d`.
"""
def __init__(self, p: float, block_size: int, inplace: bool = False, eps: float = 1e-06) -> None:
super().__init__()
self.p = p
self.block_size = block_size
self.inplace = inplace
self.eps = eps
[docs] def forward(self, input: Tensor) -> Tensor:
"""
Args:
input (Tensor): Input feature map on which some areas will be randomly
dropped.
Returns:
Tensor: The tensor after DropBlock layer.
"""
return drop_block2d(input, self.p, self.block_size, self.inplace, self.eps, self.training)
def __repr__(self) -> str:
s = f"{self.__class__.__name__}(p={self.p}, block_size={self.block_size}, inplace={self.inplace})"
return s
torch.fx.wrap("drop_block3d")
[docs]class DropBlock3d(DropBlock2d):
"""
See :func:`drop_block3d`.
"""
def __init__(self, p: float, block_size: int, inplace: bool = False, eps: float = 1e-06) -> None:
super().__init__(p, block_size, inplace, eps)
[docs] def forward(self, input: Tensor) -> Tensor:
"""
Args:
input (Tensor): Input feature map on which some areas will be randomly
dropped.
Returns:
Tensor: The tensor after DropBlock layer.
"""
return drop_block3d(input, self.p, self.block_size, self.inplace, self.eps, self.training)