File size: 6,121 Bytes
983684c
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
from collections import abc
import os

import torch
from torch.nn import functional as F
from torch.autograd import Function
from torch.utils.cpp_extension import load


module_path = os.path.dirname(__file__)
upfirdn2d_op = load(
    "upfirdn2d",
    sources=[
        os.path.join(module_path, "upfirdn2d.cpp"),
        os.path.join(module_path, "upfirdn2d_kernel.cu"),
    ],
)


class UpFirDn2dBackward(Function):
    @staticmethod
    def forward(

        ctx, grad_output, kernel, grad_kernel, up, down, pad, g_pad, in_size, out_size

    ):

        up_x, up_y = up
        down_x, down_y = down
        g_pad_x0, g_pad_x1, g_pad_y0, g_pad_y1 = g_pad

        grad_output = grad_output.reshape(-1, out_size[0], out_size[1], 1)

        grad_input = upfirdn2d_op.upfirdn2d(
            grad_output,
            grad_kernel,
            down_x,
            down_y,
            up_x,
            up_y,
            g_pad_x0,
            g_pad_x1,
            g_pad_y0,
            g_pad_y1,
        )
        grad_input = grad_input.view(in_size[0], in_size[1], in_size[2], in_size[3])

        ctx.save_for_backward(kernel)

        pad_x0, pad_x1, pad_y0, pad_y1 = pad

        ctx.up_x = up_x
        ctx.up_y = up_y
        ctx.down_x = down_x
        ctx.down_y = down_y
        ctx.pad_x0 = pad_x0
        ctx.pad_x1 = pad_x1
        ctx.pad_y0 = pad_y0
        ctx.pad_y1 = pad_y1
        ctx.in_size = in_size
        ctx.out_size = out_size

        return grad_input

    @staticmethod
    def backward(ctx, gradgrad_input):
        kernel, = ctx.saved_tensors

        gradgrad_input = gradgrad_input.reshape(-1, ctx.in_size[2], ctx.in_size[3], 1)

        gradgrad_out = upfirdn2d_op.upfirdn2d(
            gradgrad_input,
            kernel,
            ctx.up_x,
            ctx.up_y,
            ctx.down_x,
            ctx.down_y,
            ctx.pad_x0,
            ctx.pad_x1,
            ctx.pad_y0,
            ctx.pad_y1,
        )
        # gradgrad_out = gradgrad_out.view(ctx.in_size[0], ctx.out_size[0], ctx.out_size[1], ctx.in_size[3])
        gradgrad_out = gradgrad_out.view(
            ctx.in_size[0], ctx.in_size[1], ctx.out_size[0], ctx.out_size[1]
        )

        return gradgrad_out, None, None, None, None, None, None, None, None


class UpFirDn2d(Function):
    @staticmethod
    def forward(ctx, input, kernel, up, down, pad):
        up_x, up_y = up
        down_x, down_y = down
        pad_x0, pad_x1, pad_y0, pad_y1 = pad

        kernel_h, kernel_w = kernel.shape
        batch, channel, in_h, in_w = input.shape
        ctx.in_size = input.shape

        input = input.reshape(-1, in_h, in_w, 1)

        ctx.save_for_backward(kernel, torch.flip(kernel, [0, 1]))

        out_h = (in_h * up_y + pad_y0 + pad_y1 - kernel_h + down_y) // down_y
        out_w = (in_w * up_x + pad_x0 + pad_x1 - kernel_w + down_x) // down_x
        ctx.out_size = (out_h, out_w)

        ctx.up = (up_x, up_y)
        ctx.down = (down_x, down_y)
        ctx.pad = (pad_x0, pad_x1, pad_y0, pad_y1)

        g_pad_x0 = kernel_w - pad_x0 - 1
        g_pad_y0 = kernel_h - pad_y0 - 1
        g_pad_x1 = in_w * up_x - out_w * down_x + pad_x0 - up_x + 1
        g_pad_y1 = in_h * up_y - out_h * down_y + pad_y0 - up_y + 1

        ctx.g_pad = (g_pad_x0, g_pad_x1, g_pad_y0, g_pad_y1)

        out = upfirdn2d_op.upfirdn2d(
            input, kernel, up_x, up_y, down_x, down_y, pad_x0, pad_x1, pad_y0, pad_y1
        )
        # out = out.view(major, out_h, out_w, minor)
        out = out.view(-1, channel, out_h, out_w)

        return out

    @staticmethod
    def backward(ctx, grad_output):
        kernel, grad_kernel = ctx.saved_tensors

        grad_input = None

        if ctx.needs_input_grad[0]:
            grad_input = UpFirDn2dBackward.apply(
                grad_output,
                kernel,
                grad_kernel,
                ctx.up,
                ctx.down,
                ctx.pad,
                ctx.g_pad,
                ctx.in_size,
                ctx.out_size,
            )

        return grad_input, None, None, None, None


def upfirdn2d(input, kernel, up=1, down=1, pad=(0, 0)):
    if not isinstance(up, abc.Iterable):
        up = (up, up)

    if not isinstance(down, abc.Iterable):
        down = (down, down)

    if len(pad) == 2:
        pad = (pad[0], pad[1], pad[0], pad[1])

    if input.device.type == "cpu":
        out = upfirdn2d_native(input, kernel, *up, *down, *pad)

    else:
        out = UpFirDn2d.apply(input, kernel, up, down, pad)

    return out


def upfirdn2d_native(

    input, kernel, up_x, up_y, down_x, down_y, pad_x0, pad_x1, pad_y0, pad_y1

):
    _, channel, in_h, in_w = input.shape
    input = input.reshape(-1, in_h, in_w, 1)

    _, in_h, in_w, minor = input.shape
    kernel_h, kernel_w = kernel.shape

    out = input.view(-1, in_h, 1, in_w, 1, minor)
    out = F.pad(out, [0, 0, 0, up_x - 1, 0, 0, 0, up_y - 1])
    out = out.view(-1, in_h * up_y, in_w * up_x, minor)

    out = F.pad(
        out, [0, 0, max(pad_x0, 0), max(pad_x1, 0), max(pad_y0, 0), max(pad_y1, 0)]
    )
    out = out[
        :,
        max(-pad_y0, 0) : out.shape[1] - max(-pad_y1, 0),
        max(-pad_x0, 0) : out.shape[2] - max(-pad_x1, 0),
        :,
    ]

    out = out.permute(0, 3, 1, 2)
    out = out.reshape(
        [-1, 1, in_h * up_y + pad_y0 + pad_y1, in_w * up_x + pad_x0 + pad_x1]
    )
    w = torch.flip(kernel, [0, 1]).view(1, 1, kernel_h, kernel_w)
    out = F.conv2d(out, w)
    out = out.reshape(
        -1,
        minor,
        in_h * up_y + pad_y0 + pad_y1 - kernel_h + 1,
        in_w * up_x + pad_x0 + pad_x1 - kernel_w + 1,
    )
    out = out.permute(0, 2, 3, 1)
    out = out[:, ::down_y, ::down_x, :]

    out_h = (in_h * up_y + pad_y0 + pad_y1 - kernel_h + down_y) // down_y
    out_w = (in_w * up_x + pad_x0 + pad_x1 - kernel_w + down_x) // down_x

    return out.view(-1, channel, out_h, out_w)