DBNet / DB /assets /ops /dcn /functions /deform_conv.py
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import torch
from torch.autograd import Function
from torch.nn.modules.utils import _pair
from .. import deform_conv_cuda
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(
"Expected 4D tensor as input, got {}D tensor instead.".format(
input.dim()))
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_cuda.deform_conv_forward_cuda(
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
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_cuda.deform_conv_backward_input_cuda(
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_cuda.deform_conv_backward_parameters_cuda(
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 {})".format(
'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_cuda.modulated_deform_conv_cuda_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
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_cuda.modulated_deform_conv_cuda_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