import math
import torch
from torch import nn as nn
from torch.autograd import Function
from torch.autograd.function import once_differentiable
from torch.nn import functional as F
from torch.nn.modules.utils import _pair, _single
try:
from . import deform_conv_ext
except ImportError:
import os
BASICSR_JIT = os.getenv('BASICSR_JIT')
if BASICSR_JIT == 'True':
from torch.utils.cpp_extension import load
module_path = os.path.dirname(__file__)
deform_conv_ext = load(
'deform_conv',
sources=[
os.path.join(module_path, 'src', 'deform_conv_ext.cpp'),
os.path.join(module_path, 'src', 'deform_conv_cuda.cpp'),
os.path.join(module_path, 'src', 'deform_conv_cuda_kernel.cu'),
],
)
class DeformConvFunction(Function):
@staticmethod
def forward(ctx,
input,
offset,
weight,
stride=1,
padding=0,
dilation=1,
groups=1,
deformable_groups=1,
im2col_step=64):
if input is not None and input.dim() != 4:
raise ValueError(f'Expected 4D tensor as input, got {input.dim()}' 'D tensor instead.')
ctx.stride = _pair(stride)
ctx.padding = _pair(padding)
ctx.dilation = _pair(dilation)
ctx.groups = groups
ctx.deformable_groups = deformable_groups
ctx.im2col_step = im2col_step
ctx.save_for_backward(input, offset, weight)
output = input.new_empty(DeformConvFunction._output_size(input, weight, ctx.padding, ctx.dilation, ctx.stride))
ctx.bufs_ = [input.new_empty(0), input.new_empty(0)] # columns, ones
if not input.is_cuda:
raise NotImplementedError
else:
cur_im2col_step = min(ctx.im2col_step, input.shape[0])
assert (input.shape[0] % cur_im2col_step) == 0, 'im2col step must divide batchsize'
deform_conv_ext.deform_conv_forward(input, weight,
offset, output, ctx.bufs_[0], ctx.bufs_[1], weight.size(3),
weight.size(2), ctx.stride[1], ctx.stride[0], ctx.padding[1],
ctx.padding[0], ctx.dilation[1], ctx.dilation[0], ctx.groups,
ctx.deformable_groups, cur_im2col_step)
return output
@staticmethod
@once_differentiable
def backward(ctx, grad_output):
input, offset, weight = ctx.saved_tensors
grad_input = grad_offset = grad_weight = None
if not grad_output.is_cuda:
raise NotImplementedError
else:
cur_im2col_step = min(ctx.im2col_step, input.shape[0])
assert (input.shape[0] % cur_im2col_step) == 0, 'im2col step must divide batchsize'
if ctx.needs_input_grad[0] or ctx.needs_input_grad[1]:
grad_input = torch.zeros_like(input)
grad_offset = torch.zeros_like(offset)
deform_conv_ext.deform_conv_backward_input(input, offset, grad_output, grad_input,
grad_offset, weight, ctx.bufs_[0], weight.size(3),
weight.size(2), ctx.stride[1], ctx.stride[0], ctx.padding[1],
ctx.padding[0], ctx.dilation[1], ctx.dilation[0], ctx.groups,
ctx.deformable_groups, cur_im2col_step)
if ctx.needs_input_grad[2]:
grad_weight = torch.zeros_like(weight)
deform_conv_ext.deform_conv_backward_parameters(input, offset, grad_output, grad_weight,
ctx.bufs_[0], ctx.bufs_[1], weight.size(3),
weight.size(2), ctx.stride[1], ctx.stride[0],
ctx.padding[1], ctx.padding[0], ctx.dilation[1],
ctx.dilation[0], ctx.groups, ctx.deformable_groups, 1,
cur_im2col_step)
return (grad_input, grad_offset, grad_weight, None, None, None, None, None)
@staticmethod
def _output_size(input, weight, padding, dilation, stride):
channels = weight.size(0)
output_size = (input.size(0), channels)
for d in range(input.dim() - 2):
in_size = input.size(d + 2)
pad = padding[d]
kernel = dilation[d] * (weight.size(d + 2) - 1) + 1
stride_ = stride[d]
output_size += ((in_size + (2 * pad) - kernel) // stride_ + 1, )
if not all(map(lambda s: s > 0, output_size)):
raise ValueError('convolution input is too small (output would be ' f'{"x".join(map(str, output_size))})')
return output_size
class ModulatedDeformConvFunction(Function):
@staticmethod
def forward(ctx,
input,
offset,
mask,
weight,
bias=None,
stride=1,
padding=0,
dilation=1,
groups=1,
deformable_groups=1):
ctx.stride = stride
ctx.padding = padding
ctx.dilation = dilation
ctx.groups = groups
ctx.deformable_groups = deformable_groups
ctx.with_bias = bias is not None
if not ctx.with_bias:
bias = input.new_empty(1) # fake tensor
if not input.is_cuda:
raise NotImplementedError
if weight.requires_grad or mask.requires_grad or offset.requires_grad \
or input.requires_grad:
ctx.save_for_backward(input, offset, mask, weight, bias)
output = input.new_empty(ModulatedDeformConvFunction._infer_shape(ctx, input, weight))
ctx._bufs = [input.new_empty(0), input.new_empty(0)]
deform_conv_ext.modulated_deform_conv_forward(input, weight, bias, ctx._bufs[0], offset, mask, output,
ctx._bufs[1], weight.shape[2], weight.shape[3], ctx.stride,
ctx.stride, ctx.padding, ctx.padding, ctx.dilation, ctx.dilation,
ctx.groups, ctx.deformable_groups, ctx.with_bias)
return output
@staticmethod
@once_differentiable
def backward(ctx, grad_output):
if not grad_output.is_cuda:
raise NotImplementedError
input, offset, mask, weight, bias = ctx.saved_tensors
grad_input = torch.zeros_like(input)
grad_offset = torch.zeros_like(offset)
grad_mask = torch.zeros_like(mask)
grad_weight = torch.zeros_like(weight)
grad_bias = torch.zeros_like(bias)
deform_conv_ext.modulated_deform_conv_backward(input, weight, bias, ctx._bufs[0], offset, mask, ctx._bufs[1],
grad_input, grad_weight, grad_bias, grad_offset, grad_mask,
grad_output, weight.shape[2], weight.shape[3], ctx.stride,
ctx.stride, ctx.padding, ctx.padding, ctx.dilation, ctx.dilation,
ctx.groups, ctx.deformable_groups, ctx.with_bias)
if not ctx.with_bias:
grad_bias = None
return (grad_input, grad_offset, grad_mask, grad_weight, grad_bias, None, None, None, None, None)
@staticmethod
def _infer_shape(ctx, input, weight):
n = input.size(0)
channels_out = weight.size(0)
height, width = input.shape[2:4]
kernel_h, kernel_w = weight.shape[2:4]
height_out = (height + 2 * ctx.padding - (ctx.dilation * (kernel_h - 1) + 1)) // ctx.stride + 1
width_out = (width + 2 * ctx.padding - (ctx.dilation * (kernel_w - 1) + 1)) // ctx.stride + 1
return n, channels_out, height_out, width_out
deform_conv = DeformConvFunction.apply
modulated_deform_conv = ModulatedDeformConvFunction.apply
class DeformConv(nn.Module):
def __init__(self,
in_channels,
out_channels,
kernel_size,
stride=1,
padding=0,
dilation=1,
groups=1,
deformable_groups=1,
bias=False):
super(DeformConv, self).__init__()
assert not bias
assert in_channels % groups == 0, \
f'in_channels {in_channels} is not divisible by groups {groups}'
assert out_channels % groups == 0, \
f'out_channels {out_channels} is not divisible ' \
f'by groups {groups}'
self.in_channels = in_channels
self.out_channels = out_channels
self.kernel_size = _pair(kernel_size)
self.stride = _pair(stride)
self.padding = _pair(padding)
self.dilation = _pair(dilation)
self.groups = groups
self.deformable_groups = deformable_groups
# enable compatibility with nn.Conv2d
self.transposed = False
self.output_padding = _single(0)
self.weight = nn.Parameter(torch.Tensor(out_channels, in_channels // self.groups, *self.kernel_size))
self.reset_parameters()
def reset_parameters(self):
n = self.in_channels
for k in self.kernel_size:
n *= k
stdv = 1. / math.sqrt(n)
self.weight.data.uniform_(-stdv, stdv)
def forward(self, x, offset):
# To fix an assert error in deform_conv_cuda.cpp:128
# input image is smaller than kernel
input_pad = (x.size(2) < self.kernel_size[0] or x.size(3) < self.kernel_size[1])
if input_pad:
pad_h = max(self.kernel_size[0] - x.size(2), 0)
pad_w = max(self.kernel_size[1] - x.size(3), 0)
x = F.pad(x, (0, pad_w, 0, pad_h), 'constant', 0).contiguous()
offset = F.pad(offset, (0, pad_w, 0, pad_h), 'constant', 0).contiguous()
out = deform_conv(x, offset, self.weight, self.stride, self.padding, self.dilation, self.groups,
self.deformable_groups)
if input_pad:
out = out[:, :, :out.size(2) - pad_h, :out.size(3) - pad_w].contiguous()
return out
class DeformConvPack(DeformConv):
"""A Deformable Conv Encapsulation that acts as normal Conv layers.
Args:
in_channels (int): Same as nn.Conv2d.
out_channels (int): Same as nn.Conv2d.
kernel_size (int or tuple[int]): Same as nn.Conv2d.
stride (int or tuple[int]): Same as nn.Conv2d.
padding (int or tuple[int]): Same as nn.Conv2d.
dilation (int or tuple[int]): Same as nn.Conv2d.
groups (int): Same as nn.Conv2d.
bias (bool or str): If specified as `auto`, it will be decided by the
norm_cfg. Bias will be set as True if norm_cfg is None, otherwise
False.
"""
_version = 2
def __init__(self, *args, **kwargs):
super(DeformConvPack, self).__init__(*args, **kwargs)
self.conv_offset = nn.Conv2d(
self.in_channels,
self.deformable_groups * 2 * self.kernel_size[0] * self.kernel_size[1],
kernel_size=self.kernel_size,
stride=_pair(self.stride),
padding=_pair(self.padding),
dilation=_pair(self.dilation),
bias=True)
self.init_offset()
def init_offset(self):
self.conv_offset.weight.data.zero_()
self.conv_offset.bias.data.zero_()
def forward(self, x):
offset = self.conv_offset(x)
return deform_conv(x, offset, self.weight, self.stride, self.padding, self.dilation, self.groups,
self.deformable_groups)
class ModulatedDeformConv(nn.Module):
def __init__(self,
in_channels,
out_channels,
kernel_size,
stride=1,
padding=0,
dilation=1,
groups=1,
deformable_groups=1,
bias=True):
super(ModulatedDeformConv, self).__init__()
self.in_channels = in_channels
self.out_channels = out_channels
self.kernel_size = _pair(kernel_size)
self.stride = stride
self.padding = padding
self.dilation = dilation
self.groups = groups
self.deformable_groups = deformable_groups
self.with_bias = bias
# enable compatibility with nn.Conv2d
self.transposed = False
self.output_padding = _single(0)
self.weight = nn.Parameter(torch.Tensor(out_channels, in_channels // groups, *self.kernel_size))
if bias:
self.bias = nn.Parameter(torch.Tensor(out_channels))
else:
self.register_parameter('bias', None)
self.init_weights()
def init_weights(self):
n = self.in_channels
for k in self.kernel_size:
n *= k
stdv = 1. / math.sqrt(n)
self.weight.data.uniform_(-stdv, stdv)
if self.bias is not None:
self.bias.data.zero_()
def forward(self, x, offset, mask):
return modulated_deform_conv(x, offset, mask, self.weight, self.bias, self.stride, self.padding, self.dilation,
self.groups, self.deformable_groups)
class ModulatedDeformConvPack(ModulatedDeformConv):
"""A ModulatedDeformable Conv Encapsulation that acts as normal Conv layers.
Args:
in_channels (int): Same as nn.Conv2d.
out_channels (int): Same as nn.Conv2d.
kernel_size (int or tuple[int]): Same as nn.Conv2d.
stride (int or tuple[int]): Same as nn.Conv2d.
padding (int or tuple[int]): Same as nn.Conv2d.
dilation (int or tuple[int]): Same as nn.Conv2d.
groups (int): Same as nn.Conv2d.
bias (bool or str): If specified as `auto`, it will be decided by the
norm_cfg. Bias will be set as True if norm_cfg is None, otherwise
False.
"""
_version = 2
def __init__(self, *args, **kwargs):
super(ModulatedDeformConvPack, self).__init__(*args, **kwargs)
self.conv_offset = nn.Conv2d(
self.in_channels,
self.deformable_groups * 3 * self.kernel_size[0] * self.kernel_size[1],
kernel_size=self.kernel_size,
stride=_pair(self.stride),
padding=_pair(self.padding),
dilation=_pair(self.dilation),
bias=True)
self.init_weights()
def init_weights(self):
super(ModulatedDeformConvPack, self).init_weights()
if hasattr(self, 'conv_offset'):
self.conv_offset.weight.data.zero_()
self.conv_offset.bias.data.zero_()
def forward(self, x):
out = self.conv_offset(x)
o1, o2, mask = torch.chunk(out, 3, dim=1)
offset = torch.cat((o1, o2), dim=1)
mask = torch.sigmoid(mask)
return modulated_deform_conv(x, offset, mask, self.weight, self.bias, self.stride, self.padding, self.dilation,
self.groups, self.deformable_groups)