File size: 9,958 Bytes
b9d6819
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import torch
from torch import nn
from torch.nn import functional as F

from einops import rearrange
from vector_quantize_pytorch import ResidualVQ, FSQ
from .nn.quantize import ResidualVectorQuantize as DACResidualVQ


class Bottleneck(nn.Module):
    def __init__(self, is_discrete: bool = False):
        super().__init__()

        self.is_discrete = is_discrete

    def encode(self, x, return_info=False, **kwargs):
        raise NotImplementedError

    def decode(self, x):
        raise NotImplementedError


class DiscreteBottleneck(Bottleneck):
    def __init__(self, num_quantizers, codebook_size, tokens_id):
        super().__init__(is_discrete=True)

        self.num_quantizers = num_quantizers
        self.codebook_size = codebook_size
        self.tokens_id = tokens_id

    def decode_tokens(self, codes, **kwargs):
        raise NotImplementedError


class TanhBottleneck(Bottleneck):
    def __init__(self):
        super().__init__(is_discrete=False)
        self.tanh = nn.Tanh()

    def encode(self, x, return_info=False):
        info = {}

        x = torch.tanh(x)

        if return_info:
            return x, info
        else:
            return x

    def decode(self, x):
        return x


@torch.jit.script
def vae_sample_kl(mean, scale):
    stdev = nn.functional.softplus(scale) + 1e-4
    var = stdev * stdev
    logvar = torch.log(var)
    latents = torch.randn_like(mean) * stdev + mean

    kl = (mean * mean + var - logvar - 1).sum(1).mean()

    return latents, kl


@torch.jit.script
def vae_sample(mean, scale):
    stdev = nn.functional.softplus(scale) + 1e-4
    latents = torch.randn_like(mean) * stdev + mean
    return latents


class VAEBottleneck(Bottleneck):
    def __init__(self):
        super().__init__(is_discrete=False)

    def encode(self, x, return_info=False, **kwargs):
        mean, scale = x.chunk(2, dim=1)

        if return_info:
            info = {}
            x, kl = vae_sample_kl(mean, scale)
            info["kl"] = kl
            return x, info
        else:
            x = vae_sample(mean, scale)
            return x

    def decode(self, x):
        return x


def compute_mean_kernel(x, y):
    kernel_input = (x[:, None] - y[None]).pow(2).mean(2) / x.shape[-1]
    return torch.exp(-kernel_input).mean()


def compute_mmd(latents):
    latents_reshaped = latents.permute(0, 2, 1).reshape(-1, latents.shape[1])
    noise = torch.randn_like(latents_reshaped)

    latents_kernel = compute_mean_kernel(latents_reshaped, latents_reshaped)
    noise_kernel = compute_mean_kernel(noise, noise)
    latents_noise_kernel = compute_mean_kernel(latents_reshaped, noise)
    
    mmd = latents_kernel + noise_kernel - 2 * latents_noise_kernel
    return mmd.mean()


class WassersteinBottleneck(Bottleneck):
    def __init__(self, noise_augment_dim: int = 0):
        super().__init__(is_discrete=False)

        self.noise_augment_dim = noise_augment_dim
    
    def encode(self, x, return_info=False):
        info = {}

        if self.training and return_info:
            mmd = compute_mmd(x)
            info["mmd"] = mmd
        
        if return_info:
            return x, info
        
        return x

    def decode(self, x):

        if self.noise_augment_dim > 0:
            noise = torch.randn(x.shape[0], self.noise_augment_dim,
                                x.shape[-1]).type_as(x)
            x = torch.cat([x, noise], dim=1)

        return x


class L2Bottleneck(Bottleneck):
    def __init__(self):
        super().__init__(is_discrete=False)
    
    def encode(self, x, return_info=False):
        info = {}

        x = F.normalize(x, dim=1)

        if return_info:
            return x, info
        else:
            return x
        
    def decode(self, x):
        return F.normalize(x, dim=1)


class RVQBottleneck(DiscreteBottleneck):
    def __init__(self, **quantizer_kwargs):
        super().__init__(num_quantizers = quantizer_kwargs["num_quantizers"], codebook_size = quantizer_kwargs["codebook_size"], tokens_id = "quantizer_indices")
        self.quantizer = ResidualVQ(**quantizer_kwargs)
        self.num_quantizers = quantizer_kwargs["num_quantizers"]

    def encode(self, x, return_info=False, **kwargs):
        info = {}

        x = rearrange(x, "b c n -> b n c")
        x, indices, loss = self.quantizer(x)
        x = rearrange(x, "b n c -> b c n")

        info["quantizer_indices"] = indices
        info["quantizer_loss"] = loss.mean()

        if return_info:
            return x, info
        else:
            return x
        
    def decode(self, x):
        return x
    
    def decode_tokens(self, codes, **kwargs):
        latents = self.quantizer.get_outputs_from_indices(codes)

        return self.decode(latents, **kwargs)


class RVQVAEBottleneck(DiscreteBottleneck):
    def __init__(self, **quantizer_kwargs):
        super().__init__(num_quantizers = quantizer_kwargs["num_quantizers"], codebook_size = quantizer_kwargs["codebook_size"], tokens_id = "quantizer_indices")
        self.quantizer = ResidualVQ(**quantizer_kwargs)
        self.num_quantizers = quantizer_kwargs["num_quantizers"]

    def encode(self, x, return_info=False):
        info = {}

        x, kl = vae_sample(*x.chunk(2, dim=1))

        info["kl"] = kl

        x = rearrange(x, "b c n -> b n c")
        x, indices, loss = self.quantizer(x)
        x = rearrange(x, "b n c -> b c n")

        info["quantizer_indices"] = indices
        info["quantizer_loss"] = loss.mean()

        if return_info:
            return x, info
        else:
            return x
        
    def decode(self, x):
        return x
    
    def decode_tokens(self, codes, **kwargs):
        latents = self.quantizer.get_outputs_from_indices(codes)

        return self.decode(latents, **kwargs)


class DACRVQBottleneck(DiscreteBottleneck):
    def __init__(self, quantize_on_decode=False, **quantizer_kwargs):
        super().__init__(num_quantizers = quantizer_kwargs["n_codebooks"], codebook_size = quantizer_kwargs["codebook_size"], tokens_id = "codes")
        self.quantizer = DACResidualVQ(**quantizer_kwargs)
        self.num_quantizers = quantizer_kwargs["n_codebooks"]
        self.quantize_on_decode = quantize_on_decode

    def encode(self, x, return_info=False, **kwargs):
        info = {}

        info["pre_quantizer"] = x

        if self.quantize_on_decode:
            return x, info if return_info else x

        z, codes, latents, commitment_loss, codebook_loss = self.quantizer(x, **kwargs)

        output = {
            "z": z,
            "codes": codes,
            "latents": latents,
            "vq/commitment_loss": commitment_loss,
            "vq/codebook_loss": codebook_loss,
        }

        output["vq/commitment_loss"] /= self.num_quantizers
        output["vq/codebook_loss"] /= self.num_quantizers

        info.update(output)

        if return_info:
            return output["z"], info
        
        return output["z"]
    
    def decode(self, x):

        if self.quantize_on_decode:
            x = self.quantizer(x)[0]

        return x
    
    def decode_tokens(self, codes, **kwargs):
        latents, _, _ = self.quantizer.from_codes(codes)

        return self.decode(latents, **kwargs)


class DACRVQVAEBottleneck(DiscreteBottleneck):
    def __init__(self, quantize_on_decode=False, **quantizer_kwargs):
        super().__init__(num_quantizers = quantizer_kwargs["n_codebooks"], codebook_size = quantizer_kwargs["codebook_size"], tokens_id = "codes")
        self.quantizer = DACResidualVQ(**quantizer_kwargs)
        self.num_quantizers = quantizer_kwargs["n_codebooks"]
        self.quantize_on_decode = quantize_on_decode

    def encode(self, x, return_info=False, n_quantizers: int = None):
        info = {}

        mean, scale = x.chunk(2, dim=1)

        x, kl = vae_sample(mean, scale)

        info["pre_quantizer"] = x
        info["kl"] = kl

        if self.quantize_on_decode:
            return x, info if return_info else x

        z, codes, latents, commitment_loss, codebook_loss = self.quantizer(x, n_quantizers=n_quantizers)

        output = {
            "z": z,
            "codes": codes,
            "latents": latents,
            "vq/commitment_loss": commitment_loss,
            "vq/codebook_loss": codebook_loss,
        }

        output["vq/commitment_loss"] /= self.num_quantizers
        output["vq/codebook_loss"] /= self.num_quantizers

        info.update(output)

        if return_info:
            return output["z"], info
        
        return output["z"]
    
    def decode(self, x):

        if self.quantize_on_decode:
            x = self.quantizer(x)[0]

        return x

    def decode_tokens(self, codes, **kwargs):
        latents, _, _ = self.quantizer.from_codes(codes)

        return self.decode(latents, **kwargs)


class FSQBottleneck(DiscreteBottleneck):
    def __init__(self, dim, levels):
        super().__init__(num_quantizers = 1, codebook_size = levels ** dim, tokens_id = "quantizer_indices")
        self.quantizer = FSQ(levels=[levels] * dim)

    def encode(self, x, return_info=False):
        info = {}

        x = rearrange(x, "b c n -> b n c")
        x, indices = self.quantizer(x)
        x = rearrange(x, "b n c -> b c n")

        info["quantizer_indices"] = indices

        if return_info:
            return x, info
        else:
            return x
        
    def decode(self, x):
        return x
    
    def decode_tokens(self, tokens, **kwargs):
        latents = self.quantizer.indices_to_codes(tokens)

        return self.decode(latents, **kwargs)