File size: 15,574 Bytes
6c60ccc
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
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)