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  1. graph_decoder/diffusion_utils.py +542 -0
graph_decoder/diffusion_utils.py ADDED
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1
+ # Copyright 2024 the Llamole team.
2
+ #
3
+ # Licensed under the Apache License, Version 2.0 (the "License");
4
+ # you may not use this file except in compliance with the License.
5
+ # You may obtain a copy of the License at
6
+ #
7
+ # http://www.apache.org/licenses/LICENSE-2.0
8
+ #
9
+ # Unless required by applicable law or agreed to in writing, software
10
+ # distributed under the License is distributed on an "AS IS" BASIS,
11
+ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12
+ # See the License for the specific language governing permissions and
13
+ # limitations under the License.
14
+
15
+ import torch
16
+ import numpy as np
17
+ from torch.nn import functional as F
18
+ from torch_geometric.utils import to_dense_adj, to_dense_batch, remove_self_loops
19
+ import os
20
+ import json
21
+ import yaml
22
+ from types import SimpleNamespace
23
+
24
+ def dict_to_namespace(d):
25
+ return SimpleNamespace(
26
+ **{k: dict_to_namespace(v) if isinstance(v, dict) else v for k, v in d.items()}
27
+ )
28
+
29
+ class DataInfos:
30
+ def __init__(self, meta_filename="data.meta.json"):
31
+ self.all_targets = ['CH4', 'CO2', 'H2', 'N2', 'O2']
32
+ self.task_type = "gas_permeability"
33
+ if os.path.exists(meta_filename):
34
+ with open(meta_filename, "r") as f:
35
+ meta_dict = json.load(f)
36
+ else:
37
+ raise FileNotFoundError(f"Meta file {meta_filename} not found.")
38
+
39
+ self.active_atoms = meta_dict["active_atoms"]
40
+ self.max_n_nodes = meta_dict["max_node"]
41
+ self.original_max_n_nodes = meta_dict["max_node"]
42
+ self.n_nodes = torch.Tensor(meta_dict["n_atoms_per_mol_dist"])
43
+ self.edge_types = torch.Tensor(meta_dict["bond_type_dist"])
44
+ self.transition_E = torch.Tensor(meta_dict["transition_E"])
45
+
46
+ self.atom_decoder = meta_dict["active_atoms"]
47
+ node_types = torch.Tensor(meta_dict["atom_type_dist"])
48
+ active_index = (node_types > 0).nonzero().squeeze()
49
+ self.node_types = torch.Tensor(meta_dict["atom_type_dist"])[active_index]
50
+ self.nodes_dist = DistributionNodes(self.n_nodes)
51
+ self.active_index = active_index
52
+
53
+ val_len = 3 * self.original_max_n_nodes - 2
54
+ meta_val = torch.Tensor(meta_dict["valencies"])
55
+ self.valency_distribution = torch.zeros(val_len)
56
+ val_len = min(val_len, len(meta_val))
57
+ self.valency_distribution[:val_len] = meta_val[:val_len]
58
+ ## for all
59
+ self.input_dims = {"X": len(self.active_atoms), "E": 5, "y": 5}
60
+ self.output_dims = {"X": len(self.active_atoms), "E": 5, "y": 5}
61
+ # self.input_dims = {"X": 11, "E": 5, "y": 5}
62
+ # self.output_dims = {"X": 11, "E": 5, "y": 5}
63
+
64
+ def load_config(config_path, data_meta_info_path):
65
+ if not os.path.exists(config_path):
66
+ raise FileNotFoundError(f"Configuration file not found: {config_path}")
67
+
68
+ if not os.path.exists(data_meta_info_path):
69
+ raise FileNotFoundError(f"Data meta info file not found: {data_meta_info_path}")
70
+
71
+ with open(config_path, "r") as file:
72
+ cfg_dict = yaml.safe_load(file)
73
+
74
+ cfg = dict_to_namespace(cfg_dict)
75
+
76
+ data_info = DataInfos(data_meta_info_path)
77
+ return cfg, data_info
78
+
79
+
80
+ #### graph utils
81
+ class PlaceHolder:
82
+ def __init__(self, X, E, y):
83
+ self.X = X
84
+ self.E = E
85
+ self.y = y
86
+
87
+ def type_as(self, x: torch.Tensor, categorical: bool = False):
88
+ """Changes the device and dtype of X, E, y."""
89
+ self.X = self.X.type_as(x)
90
+ self.E = self.E.type_as(x)
91
+ if categorical:
92
+ self.y = self.y.type_as(x)
93
+ return self
94
+
95
+ def mask(self, node_mask, collapse=False):
96
+ x_mask = node_mask.unsqueeze(-1) # bs, n, 1
97
+ e_mask1 = x_mask.unsqueeze(2) # bs, n, 1, 1
98
+ e_mask2 = x_mask.unsqueeze(1) # bs, 1, n, 1
99
+
100
+ if collapse:
101
+ self.X = torch.argmax(self.X, dim=-1)
102
+ self.E = torch.argmax(self.E, dim=-1)
103
+
104
+ self.X[node_mask == 0] = -1
105
+ self.E[(e_mask1 * e_mask2).squeeze(-1) == 0] = -1
106
+ else:
107
+ self.X = self.X * x_mask
108
+ self.E = self.E * e_mask1 * e_mask2
109
+ assert torch.allclose(self.E, torch.transpose(self.E, 1, 2))
110
+ return self
111
+
112
+
113
+ def to_dense(x, edge_index, edge_attr, batch, max_num_nodes=None):
114
+ X, node_mask = to_dense_batch(x=x, batch=batch, max_num_nodes=max_num_nodes)
115
+ # node_mask = node_mask.float()
116
+ edge_index, edge_attr = remove_self_loops(edge_index, edge_attr)
117
+ if max_num_nodes is None:
118
+ max_num_nodes = X.size(1)
119
+ E = to_dense_adj(
120
+ edge_index=edge_index,
121
+ batch=batch,
122
+ edge_attr=edge_attr,
123
+ max_num_nodes=max_num_nodes,
124
+ )
125
+ E = encode_no_edge(E)
126
+ return PlaceHolder(X=X, E=E, y=None), node_mask
127
+
128
+
129
+ def encode_no_edge(E):
130
+ assert len(E.shape) == 4
131
+ if E.shape[-1] == 0:
132
+ return E
133
+ no_edge = torch.sum(E, dim=3) == 0
134
+ first_elt = E[:, :, :, 0]
135
+ first_elt[no_edge] = 1
136
+ E[:, :, :, 0] = first_elt
137
+ diag = (
138
+ torch.eye(E.shape[1], dtype=torch.bool).unsqueeze(0).expand(E.shape[0], -1, -1)
139
+ )
140
+ E[diag] = 0
141
+ return E
142
+
143
+
144
+ #### diffusion utils
145
+ class DistributionNodes:
146
+ def __init__(self, histogram):
147
+ """Compute the distribution of the number of nodes in the dataset, and sample from this distribution.
148
+ historgram: dict. The keys are num_nodes, the values are counts
149
+ """
150
+
151
+ if type(histogram) == dict:
152
+ max_n_nodes = max(histogram.keys())
153
+ prob = torch.zeros(max_n_nodes + 1)
154
+ for num_nodes, count in histogram.items():
155
+ prob[num_nodes] = count
156
+ else:
157
+ prob = histogram
158
+
159
+ self.prob = prob / prob.sum()
160
+ self.m = torch.distributions.Categorical(prob)
161
+
162
+ def sample_n(self, n_samples, device):
163
+ idx = self.m.sample((n_samples,))
164
+ return idx.to(device)
165
+
166
+ def log_prob(self, batch_n_nodes):
167
+ assert len(batch_n_nodes.size()) == 1
168
+ p = self.prob.to(batch_n_nodes.device)
169
+
170
+ probas = p[batch_n_nodes]
171
+ log_p = torch.log(probas + 1e-30)
172
+ return log_p
173
+
174
+
175
+ class PredefinedNoiseScheduleDiscrete(torch.nn.Module):
176
+ def __init__(self, noise_schedule, timesteps):
177
+ super(PredefinedNoiseScheduleDiscrete, self).__init__()
178
+ self.timesteps = timesteps
179
+
180
+ betas = cosine_beta_schedule_discrete(timesteps)
181
+ self.register_buffer("betas", torch.from_numpy(betas).float())
182
+
183
+ # 0.9999
184
+ self.alphas = 1 - torch.clamp(self.betas, min=0, max=1)
185
+
186
+ log_alpha = torch.log(self.alphas)
187
+ log_alpha_bar = torch.cumsum(log_alpha, dim=0)
188
+ self.alphas_bar = torch.exp(log_alpha_bar)
189
+
190
+ def forward(self, t_normalized=None, t_int=None):
191
+ assert int(t_normalized is None) + int(t_int is None) == 1
192
+ if t_int is None:
193
+ t_int = torch.round(t_normalized * self.timesteps)
194
+ self.betas = self.betas.type_as(t_int)
195
+ return self.betas[t_int.long()]
196
+
197
+ def get_alpha_bar(self, t_normalized=None, t_int=None):
198
+ assert int(t_normalized is None) + int(t_int is None) == 1
199
+ if t_int is None:
200
+ t_int = torch.round(t_normalized * self.timesteps)
201
+ self.alphas_bar = self.alphas_bar.type_as(t_int)
202
+ return self.alphas_bar[t_int.long()]
203
+
204
+
205
+ class DiscreteUniformTransition:
206
+ def __init__(self, x_classes: int, e_classes: int, y_classes: int):
207
+ self.X_classes = x_classes
208
+ self.E_classes = e_classes
209
+ self.y_classes = y_classes
210
+ self.u_x = torch.ones(1, self.X_classes, self.X_classes)
211
+ if self.X_classes > 0:
212
+ self.u_x = self.u_x / self.X_classes
213
+
214
+ self.u_e = torch.ones(1, self.E_classes, self.E_classes)
215
+ if self.E_classes > 0:
216
+ self.u_e = self.u_e / self.E_classes
217
+
218
+ self.u_y = torch.ones(1, self.y_classes, self.y_classes)
219
+ if self.y_classes > 0:
220
+ self.u_y = self.u_y / self.y_classes
221
+
222
+ def get_Qt(self, beta_t, device, X=None, flatten_e=None):
223
+ """Returns one-step transition matrices for X and E, from step t - 1 to step t.
224
+ Qt = (1 - beta_t) * I + beta_t / K
225
+
226
+ beta_t: (bs) noise level between 0 and 1
227
+ returns: qx (bs, dx, dx), qe (bs, de, de), qy (bs, dy, dy).
228
+ """
229
+ beta_t = beta_t.unsqueeze(1)
230
+ beta_t = beta_t.to(device)
231
+ self.u_x = self.u_x.to(device)
232
+ self.u_e = self.u_e.to(device)
233
+ self.u_y = self.u_y.to(device)
234
+
235
+ q_x = beta_t * self.u_x + (1 - beta_t) * torch.eye(
236
+ self.X_classes, device=device
237
+ ).unsqueeze(0)
238
+ q_e = beta_t * self.u_e + (1 - beta_t) * torch.eye(
239
+ self.E_classes, device=device
240
+ ).unsqueeze(0)
241
+ q_y = beta_t * self.u_y + (1 - beta_t) * torch.eye(
242
+ self.y_classes, device=device
243
+ ).unsqueeze(0)
244
+
245
+ return PlaceHolder(X=q_x, E=q_e, y=q_y)
246
+
247
+ def get_Qt_bar(self, alpha_bar_t, device, X=None, flatten_e=None):
248
+ """Returns t-step transition matrices for X and E, from step 0 to step t.
249
+ Qt = prod(1 - beta_t) * I + (1 - prod(1 - beta_t)) / K
250
+
251
+ alpha_bar_t: (bs) Product of the (1 - beta_t) for each time step from 0 to t.
252
+ returns: qx (bs, dx, dx), qe (bs, de, de), qy (bs, dy, dy).
253
+ """
254
+ alpha_bar_t = alpha_bar_t.unsqueeze(1)
255
+ alpha_bar_t = alpha_bar_t.to(device)
256
+ self.u_x = self.u_x.to(device)
257
+ self.u_e = self.u_e.to(device)
258
+ self.u_y = self.u_y.to(device)
259
+
260
+ q_x = (
261
+ alpha_bar_t * torch.eye(self.X_classes, device=device).unsqueeze(0)
262
+ + (1 - alpha_bar_t) * self.u_x
263
+ )
264
+ q_e = (
265
+ alpha_bar_t * torch.eye(self.E_classes, device=device).unsqueeze(0)
266
+ + (1 - alpha_bar_t) * self.u_e
267
+ )
268
+ q_y = (
269
+ alpha_bar_t * torch.eye(self.y_classes, device=device).unsqueeze(0)
270
+ + (1 - alpha_bar_t) * self.u_y
271
+ )
272
+
273
+ return PlaceHolder(X=q_x, E=q_e, y=q_y)
274
+
275
+
276
+ class MarginalTransition:
277
+ def __init__(
278
+ self, x_marginals, e_marginals, xe_conditions, ex_conditions, y_classes, n_nodes
279
+ ):
280
+ self.X_classes = len(x_marginals)
281
+ self.E_classes = len(e_marginals)
282
+ self.y_classes = y_classes
283
+ self.x_marginals = x_marginals # Dx
284
+ self.e_marginals = e_marginals # Dx, De
285
+ self.xe_conditions = xe_conditions
286
+ # print('e_marginals.dtype', e_marginals.dtype)
287
+ # print('x_marginals.dtype', x_marginals.dtype)
288
+ # print('xe_conditions.dtype', xe_conditions.dtype)
289
+
290
+ self.u_x = (
291
+ x_marginals.unsqueeze(0).expand(self.X_classes, -1).unsqueeze(0)
292
+ ) # 1, Dx, Dx
293
+ self.u_e = (
294
+ e_marginals.unsqueeze(0).expand(self.E_classes, -1).unsqueeze(0)
295
+ ) # 1, De, De
296
+ self.u_xe = xe_conditions.unsqueeze(0) # 1, Dx, De
297
+ self.u_ex = ex_conditions.unsqueeze(0) # 1, De, Dx
298
+ self.u = self.get_union_transition(
299
+ self.u_x, self.u_e, self.u_xe, self.u_ex, n_nodes
300
+ ) # 1, Dx + n*De, Dx + n*De
301
+
302
+ def get_union_transition(self, u_x, u_e, u_xe, u_ex, n_nodes):
303
+ u_e = u_e.repeat(1, n_nodes, n_nodes) # (1, n*de, n*de)
304
+ u_xe = u_xe.repeat(1, 1, n_nodes) # (1, dx, n*de)
305
+ u_ex = u_ex.repeat(1, n_nodes, 1) # (1, n*de, dx)
306
+ u0 = torch.cat([u_x, u_xe], dim=2) # (1, dx, dx + n*de)
307
+ u1 = torch.cat([u_ex, u_e], dim=2) # (1, n*de, dx + n*de)
308
+ u = torch.cat([u0, u1], dim=1) # (1, dx + n*de, dx + n*de)
309
+ return u
310
+
311
+ def index_edge_margin(self, X, q_e, n_bond=5):
312
+ # q_e: (bs, dx, de) --> (bs, n, de)
313
+ bs, n, n_atom = X.shape
314
+ node_indices = X.argmax(-1) # (bs, n)
315
+ ind = node_indices[:, :, None].expand(bs, n, n_bond)
316
+ q_e = torch.gather(q_e, 1, ind)
317
+ return q_e
318
+
319
+ def get_Qt(self, beta_t, device):
320
+ """Returns one-step transition matrices for X and E, from step t - 1 to step t.
321
+ Qt = (1 - beta_t) * I + beta_t / K
322
+ beta_t: (bs)
323
+ returns: q (bs, d0, d0)
324
+ """
325
+ bs = beta_t.size(0)
326
+ d0 = self.u.size(-1)
327
+ self.u = self.u.to(device)
328
+ u = self.u.expand(bs, d0, d0)
329
+
330
+ beta_t = beta_t.to(device)
331
+ beta_t = beta_t.view(bs, 1, 1)
332
+ q = beta_t * u + (1 - beta_t) * torch.eye(d0, device=device, dtype=self.u.dtype).unsqueeze(0)
333
+
334
+ return PlaceHolder(X=q, E=None, y=None)
335
+
336
+ def get_Qt_bar(self, alpha_bar_t, device):
337
+ """Returns t-step transition matrices for X and E, from step 0 to step t.
338
+ Qt = prod(1 - beta_t) * I + (1 - prod(1 - beta_t)) * K
339
+ alpha_bar_t: (bs, 1) roduct of the (1 - beta_t) for each time step from 0 to t.
340
+ returns: q (bs, d0, d0)
341
+ """
342
+ bs = alpha_bar_t.size(0)
343
+ d0 = self.u.size(-1)
344
+ alpha_bar_t = alpha_bar_t.to(device)
345
+ alpha_bar_t = alpha_bar_t.view(bs, 1, 1)
346
+ self.u = self.u.to(device)
347
+ q = (
348
+ alpha_bar_t * torch.eye(d0, device=device, dtype=self.u.dtype).unsqueeze(0)
349
+ + (1 - alpha_bar_t) * self.u
350
+ )
351
+
352
+ return PlaceHolder(X=q, E=None, y=None)
353
+
354
+
355
+ def sum_except_batch(x):
356
+ return x.reshape(x.size(0), -1).sum(dim=-1)
357
+
358
+
359
+ def assert_correctly_masked(variable, node_mask):
360
+ assert (
361
+ variable * (1 - node_mask.long())
362
+ ).abs().max().item() < 1e-4, "Variables not masked properly."
363
+
364
+
365
+ def cosine_beta_schedule_discrete(timesteps, s=0.008):
366
+ """Cosine schedule as proposed in https://openreview.net/forum?id=-NEXDKk8gZ."""
367
+ steps = timesteps + 2
368
+ x = np.linspace(0, steps, steps)
369
+
370
+ alphas_cumprod = np.cos(0.5 * np.pi * ((x / steps) + s) / (1 + s)) ** 2
371
+ alphas_cumprod = alphas_cumprod / alphas_cumprod[0]
372
+ alphas = alphas_cumprod[1:] / alphas_cumprod[:-1]
373
+ betas = 1 - alphas
374
+ return betas.squeeze()
375
+
376
+
377
+ def sample_discrete_features(probX, probE, node_mask, step=None, add_nose=True):
378
+ """Sample features from multinomial distribution with given probabilities (probX, probE, proby)
379
+ :param probX: bs, n, dx_out node features
380
+ :param probE: bs, n, n, de_out edge features
381
+ :param proby: bs, dy_out global features.
382
+ """
383
+ bs, n, _ = probX.shape
384
+
385
+ # Noise X
386
+ # The masked rows should define probability distributions as well
387
+ probX[~node_mask] = 1 / probX.shape[-1]
388
+
389
+ # Flatten the probability tensor to sample with multinomial
390
+ probX = probX.reshape(bs * n, -1) # (bs * n, dx_out)
391
+
392
+ # Sample X
393
+ probX = probX.clamp_min(1e-5)
394
+ probX = probX / probX.sum(dim=-1, keepdim=True)
395
+ X_t = probX.multinomial(1) # (bs * n, 1)
396
+ X_t = X_t.reshape(bs, n) # (bs, n)
397
+
398
+ # Noise E
399
+ # The masked rows should define probability distributions as well
400
+ inverse_edge_mask = ~(node_mask.unsqueeze(1) * node_mask.unsqueeze(2))
401
+ diag_mask = torch.eye(n).unsqueeze(0).expand(bs, -1, -1)
402
+
403
+ probE[inverse_edge_mask] = 1 / probE.shape[-1]
404
+ probE[diag_mask.bool()] = 1 / probE.shape[-1]
405
+ probE = probE.reshape(bs * n * n, -1) # (bs * n * n, de_out)
406
+ probE = probE.clamp_min(1e-5)
407
+ probE = probE / probE.sum(dim=-1, keepdim=True)
408
+
409
+ # Sample E
410
+ E_t = probE.multinomial(1).reshape(bs, n, n) # (bs, n, n)
411
+ E_t = torch.triu(E_t, diagonal=1)
412
+ E_t = E_t + torch.transpose(E_t, 1, 2)
413
+
414
+ return PlaceHolder(X=X_t, E=E_t, y=torch.zeros(bs, 0).type_as(X_t))
415
+
416
+
417
+ def mask_distributions(true_X, true_E, pred_X, pred_E, node_mask):
418
+ # Add a small value everywhere to avoid nans
419
+ pred_X = pred_X.clamp_min(1e-5)
420
+ pred_X = pred_X / torch.sum(pred_X, dim=-1, keepdim=True)
421
+
422
+ pred_E = pred_E.clamp_min(1e-5)
423
+ pred_E = pred_E / torch.sum(pred_E, dim=-1, keepdim=True)
424
+
425
+ # Set masked rows to arbitrary distributions, so it doesn't contribute to loss
426
+ row_X = torch.ones(true_X.size(-1), dtype=true_X.dtype, device=true_X.device)
427
+ row_E = torch.zeros(
428
+ true_E.size(-1), dtype=true_E.dtype, device=true_E.device
429
+ ).clamp_min(1e-5)
430
+ row_E[0] = 1.0
431
+
432
+ diag_mask = ~torch.eye(
433
+ node_mask.size(1), device=node_mask.device, dtype=torch.bool
434
+ ).unsqueeze(0)
435
+ true_X[~node_mask] = row_X
436
+ true_E[~(node_mask.unsqueeze(1) * node_mask.unsqueeze(2) * diag_mask), :] = row_E
437
+ pred_X[~node_mask] = row_X.type_as(pred_X)
438
+ pred_E[~(node_mask.unsqueeze(1) * node_mask.unsqueeze(2) * diag_mask), :] = (
439
+ row_E.type_as(pred_E)
440
+ )
441
+
442
+ return true_X, true_E, pred_X, pred_E
443
+
444
+
445
+ def forward_diffusion(X, X_t, Qt, Qsb, Qtb, X_dim):
446
+ bs, n, d = X.shape
447
+
448
+ Qt_X_T = torch.transpose(Qt.X, -2, -1) # (bs, d, d)
449
+ left_term = X_t @ Qt_X_T # (bs, N, d)
450
+ right_term = X @ Qsb.X # (bs, N, d)
451
+
452
+ numerator = left_term * right_term # (bs, N, d)
453
+ denominator = X @ Qtb.X # (bs, N, d) @ (bs, d, d) = (bs, N, d)
454
+ denominator = denominator * X_t
455
+
456
+ num_X = numerator[:, :, :X_dim]
457
+ num_E = numerator[:, :, X_dim:].reshape(bs, n * n, -1)
458
+
459
+ deno_X = denominator[:, :, :X_dim]
460
+ deno_E = denominator[:, :, X_dim:].reshape(bs, n * n, -1)
461
+
462
+ denominator = denominator.unsqueeze(-1) # (bs, N, 1)
463
+
464
+ deno_X = deno_X.sum(dim=-1, keepdim=True)
465
+ deno_E = deno_E.sum(dim=-1, keepdim=True)
466
+
467
+ deno_X[deno_X == 0.0] = 1
468
+ deno_E[deno_E == 0.0] = 1
469
+ prob_X = num_X / deno_X
470
+ prob_E = num_E / deno_E
471
+
472
+ prob_E = prob_E / prob_E.sum(dim=-1, keepdim=True)
473
+ prob_X = prob_X / prob_X.sum(dim=-1, keepdim=True)
474
+ return PlaceHolder(X=prob_X, E=prob_E, y=None)
475
+
476
+
477
+ def reverse_diffusion(predX_0, X_t, Qt, Qsb, Qtb):
478
+ """M: X or E
479
+ Compute xt @ Qt.T * x0 @ Qsb / x0 @ Qtb @ xt.T for each possible value of x0
480
+ X_t: bs, n, dt or bs, n, n, dt
481
+ Qt: bs, d_t-1, dt
482
+ Qsb: bs, d0, d_t-1
483
+ Qtb: bs, d0, dt.
484
+ """
485
+ Qt_T = Qt.transpose(-1, -2) # bs, N, dt
486
+ assert Qt.dim() == 3
487
+ left_term = X_t @ Qt_T # bs, N, d_t-1
488
+ right_term = predX_0 @ Qsb
489
+ numerator = left_term * right_term # bs, N, d_t-1
490
+
491
+ denominator = Qtb @ X_t.transpose(-1, -2) # bs, d0, N
492
+ denominator = denominator.transpose(-1, -2) # bs, N, d0
493
+ return numerator / denominator.clamp_min(1e-5)
494
+
495
+ def reverse_tensor(x):
496
+ return x[torch.arange(x.size(0) - 1, -1, -1)]
497
+
498
+ def sample_discrete_feature_noise(limit_dist, node_mask):
499
+ """Sample from the limit distribution of the diffusion process"""
500
+ bs, n_max = node_mask.shape
501
+ x_limit = limit_dist.X[None, None, :].expand(bs, n_max, -1)
502
+ x_limit = x_limit.to(node_mask.device)
503
+
504
+ U_X = x_limit.flatten(end_dim=-2).multinomial(1).reshape(bs, n_max)
505
+ U_X = F.one_hot(U_X.long(), num_classes=x_limit.shape[-1]).type_as(x_limit)
506
+
507
+ e_limit = limit_dist.E[None, None, None, :].expand(bs, n_max, n_max, -1)
508
+ U_E = e_limit.flatten(end_dim=-2).multinomial(1).reshape(bs, n_max, n_max)
509
+ U_E = F.one_hot(U_E.long(), num_classes=e_limit.shape[-1]).type_as(x_limit)
510
+
511
+ U_X = U_X.to(node_mask.device)
512
+ U_E = U_E.to(node_mask.device)
513
+
514
+ # Get upper triangular part of edge noise, without main diagonal
515
+ upper_triangular_mask = torch.zeros_like(U_E)
516
+ indices = torch.triu_indices(row=U_E.size(1), col=U_E.size(2), offset=1)
517
+ upper_triangular_mask[:, indices[0], indices[1], :] = 1
518
+
519
+ U_E = U_E * upper_triangular_mask
520
+ U_E = U_E + torch.transpose(U_E, 1, 2)
521
+
522
+ assert (U_E == torch.transpose(U_E, 1, 2)).all()
523
+ return PlaceHolder(X=U_X, E=U_E, y=None).mask(node_mask)
524
+
525
+
526
+ def index_QE(X, q_e, n_bond=5):
527
+ bs, n, n_atom = X.shape
528
+ node_indices = X.argmax(-1) # (bs, n)
529
+
530
+ exp_ind1 = node_indices[:, :, None, None, None].expand(
531
+ bs, n, n_atom, n_bond, n_bond
532
+ )
533
+ exp_ind2 = node_indices[:, :, None, None, None].expand(bs, n, n, n_bond, n_bond)
534
+
535
+ q_e = torch.gather(q_e, 1, exp_ind1)
536
+ q_e = torch.gather(q_e, 2, exp_ind2) # (bs, n, n, n_bond, n_bond)
537
+
538
+ node_mask = X.sum(-1) != 0
539
+ no_edge = (~node_mask)[:, :, None] & (~node_mask)[:, None, :]
540
+ q_e[no_edge] = torch.tensor([1, 0, 0, 0, 0]).type_as(q_e)
541
+
542
+ return q_e