|
1 |
| -#!/usr/bin/env python3 |
2 |
| -# Copyright (c) Meta Platforms, Inc. and affiliates. |
3 |
| -# |
4 |
| -# This source code is licensed under the MIT license found in the |
5 |
| -# LICENSE file in the root directory of this source tree. |
6 |
| - |
7 |
| -r""" |
8 |
| -Latent Information Gain Acquisition Function for Neural Process Models. |
9 |
| -
|
10 |
| -References: |
11 |
| -
|
12 |
| -.. [Wu2023arxiv] |
13 |
| - Wu, D., Niu, R., Chinazzi, M., Vespignani, A., Ma, Y.-A., & Yu, R. (2023). |
14 |
| - Deep Bayesian Active Learning for Accelerating Stochastic Simulation. |
15 |
| - arXiv preprint arXiv:2106.02770. Retrieved from https://arxiv.org/abs/2106.02770 |
16 |
| -
|
17 |
| -Contributor: eibarolle |
18 |
| -""" |
19 |
| - |
20 |
| -from __future__ import annotations |
21 |
| - |
22 |
| -from typing import Any, Type |
23 |
| - |
24 |
| -import torch |
25 |
| -from botorch.acquisition import AcquisitionFunction |
26 |
| -from botorch_community.models.np_regression import NeuralProcessModel |
27 |
| -from torch import Tensor |
28 |
| -# reference: https://arxiv.org/abs/2106.02770 |
29 |
| - |
30 |
| - |
31 |
| -class LatentInformationGain(AcquisitionFunction): |
32 |
| - def __init__( |
33 |
| - self, |
34 |
| - model: Type[Any], |
35 |
| - num_samples: int = 10, |
36 |
| - min_std: float = 0.01, |
37 |
| - scaler: float = 0.5, |
38 |
| - ) -> None: |
39 |
| - """ |
40 |
| - Latent Information Gain (LIG) Acquisition Function. |
41 |
| - Uses the model's built-in posterior function to generalize KL computation. |
42 |
| -
|
43 |
| - Args: |
44 |
| - model: The model class to be used, defaults to NeuralProcessModel. |
45 |
| - num_samples: Int showing the # of samples for calculation, defaults to 10. |
46 |
| - min_std: Float representing the minimum possible standardized std, |
47 |
| - defaults to 0.01. |
48 |
| - scaler: Float scaling the std, defaults to 0.5. |
49 |
| - """ |
50 |
| - super().__init__(model) |
51 |
| - self.model = model |
52 |
| - self.num_samples = num_samples |
53 |
| - self.min_std = min_std |
54 |
| - self.scaler = scaler |
55 |
| - |
56 |
| - def forward(self, candidate_x: Tensor) -> Tensor: |
57 |
| - """ |
58 |
| - Conduct the Latent Information Gain acquisition function for the inputs. |
59 |
| -
|
60 |
| - Args: |
61 |
| - candidate_x: Candidate input points, as a Tensor. Ideally in the shape |
62 |
| - (N, q, D). |
63 |
| -
|
64 |
| - Returns: |
65 |
| - torch.Tensor: The LIG scores of computed KLDs, in the shape (N, q). |
66 |
| - """ |
67 |
| - device = candidate_x.device |
68 |
| - candidate_x = candidate_x.to(device) |
69 |
| - N, q, D = candidate_x.shape |
70 |
| - kl = torch.zeros(N, device=device, dtype=torch.float32) |
71 |
| - |
72 |
| - if isinstance(self.model, NeuralProcessModel): |
73 |
| - x_c, y_c, _, _ = self.model.random_split_context_target( |
74 |
| - self.model.train_X, self.model.train_Y, self.model.n_context |
75 |
| - ) |
76 |
| - self.model.z_mu_context, self.model.z_logvar_context = ( |
77 |
| - self.model.data_to_z_params(x_c, y_c) |
78 |
| - ) |
79 |
| - |
80 |
| - for i in range(N): |
81 |
| - x_i = candidate_x[i] |
82 |
| - kl_i = 0.0 |
83 |
| - |
84 |
| - for _ in range(self.num_samples): |
85 |
| - sample_z = self.model.sample_z( |
86 |
| - self.model.z_mu_context, self.model.z_logvar_context |
87 |
| - ) |
88 |
| - if sample_z.dim() == 1: |
89 |
| - sample_z = sample_z.unsqueeze(0) |
90 |
| - |
91 |
| - y_pred = self.model.decoder(x_i, sample_z) |
92 |
| - |
93 |
| - combined_x = torch.cat([x_c, x_i], dim=0) |
94 |
| - combined_y = torch.cat([y_c, y_pred], dim=0) |
95 |
| - |
96 |
| - self.model.z_mu_all, self.model.z_logvar_all = ( |
97 |
| - self.model.data_to_z_params(combined_x, combined_y) |
98 |
| - ) |
99 |
| - kl_sample = self.model.KLD_gaussian(self.min_std, self.scaler) |
100 |
| - kl_i += kl_sample |
101 |
| - |
102 |
| - kl[i] = kl_i / self.num_samples |
103 |
| - |
104 |
| - else: |
105 |
| - for i in range(N): |
106 |
| - x_i = candidate_x[i] |
107 |
| - kl_i = 0.0 |
108 |
| - for _ in range(self.num_samples): |
109 |
| - posterior_prior = self.model.posterior(self.model.train_X) |
110 |
| - posterior_candidate = self.model.posterior(x_i) |
111 |
| - |
112 |
| - kl_i += torch.distributions.kl_divergence( |
113 |
| - posterior_candidate.mvn, posterior_prior.mvn |
114 |
| - ).sum() |
115 |
| - |
116 |
| - kl[i] = kl_i / self.num_samples |
117 |
| - return kl |
| 1 | +#!/usr/bin/env python3 |
| 2 | +# Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | +# |
| 4 | +# This source code is licensed under the MIT license found in the |
| 5 | +# LICENSE file in the root directory of this source tree. |
| 6 | + |
| 7 | +r""" |
| 8 | +Latent Information Gain Acquisition Function for Neural Process Models. |
| 9 | +
|
| 10 | +References: |
| 11 | +
|
| 12 | +.. [Wu2023arxiv] |
| 13 | + Wu, D., Niu, R., Chinazzi, M., Vespignani, A., Ma, Y.-A., & Yu, R. (2023). |
| 14 | + Deep Bayesian Active Learning for Accelerating Stochastic Simulation. |
| 15 | + arXiv preprint arXiv:2106.02770. Retrieved from https://arxiv.org/abs/2106.02770 |
| 16 | +
|
| 17 | +Contributor: eibarolle |
| 18 | +""" |
| 19 | + |
| 20 | +from __future__ import annotations |
| 21 | + |
| 22 | +from typing import Any, Type |
| 23 | + |
| 24 | +import torch |
| 25 | +from botorch.acquisition import AcquisitionFunction |
| 26 | +from botorch_community.models.np_regression import NeuralProcessModel |
| 27 | +from torch import Tensor |
| 28 | +# reference: https://arxiv.org/abs/2106.02770 |
| 29 | + |
| 30 | + |
| 31 | +class LatentInformationGain(AcquisitionFunction): |
| 32 | + def __init__( |
| 33 | + self, |
| 34 | + model: Type[Any], |
| 35 | + num_samples: int = 10, |
| 36 | + min_std: float = 0.01, |
| 37 | + scaler: float = 0.5, |
| 38 | + ) -> None: |
| 39 | + """ |
| 40 | + Latent Information Gain (LIG) Acquisition Function. |
| 41 | + Uses the model's built-in posterior function to generalize KL computation. |
| 42 | +
|
| 43 | + Args: |
| 44 | + model: The model class to be used, defaults to NeuralProcessModel. |
| 45 | + num_samples: Int showing the # of samples for calculation, defaults to 10. |
| 46 | + min_std: Float representing the minimum possible standardized std, |
| 47 | + defaults to 0.01. |
| 48 | + scaler: Float scaling the std, defaults to 0.5. |
| 49 | + """ |
| 50 | + super().__init__(model) |
| 51 | + self.model = model |
| 52 | + self.num_samples = num_samples |
| 53 | + self.min_std = min_std |
| 54 | + self.scaler = scaler |
| 55 | + |
| 56 | + def forward(self, candidate_x: Tensor) -> Tensor: |
| 57 | + """ |
| 58 | + Conduct the Latent Information Gain acquisition function for the inputs. |
| 59 | +
|
| 60 | + Args: |
| 61 | + candidate_x: Candidate input points, as a Tensor. Ideally in the shape |
| 62 | + (N, q, D). |
| 63 | +
|
| 64 | + Returns: |
| 65 | + torch.Tensor: The LIG scores of computed KLDs, in the shape (N, q). |
| 66 | + """ |
| 67 | + device = candidate_x.device |
| 68 | + candidate_x = candidate_x.to(device) |
| 69 | + N, q, D = candidate_x.shape |
| 70 | + kl = torch.zeros(N, device=device, dtype=torch.float32) |
| 71 | + |
| 72 | + if isinstance(self.model, NeuralProcessModel): |
| 73 | + x_c, y_c, _, _ = self.model.random_split_context_target( |
| 74 | + self.model.train_X, self.model.train_Y, self.model.n_context |
| 75 | + ) |
| 76 | + self.model.z_mu_context, self.model.z_logvar_context = ( |
| 77 | + self.model.data_to_z_params(x_c, y_c) |
| 78 | + ) |
| 79 | + |
| 80 | + for i in range(N): |
| 81 | + x_i = candidate_x[i] |
| 82 | + kl_i = 0.0 |
| 83 | + |
| 84 | + for _ in range(self.num_samples): |
| 85 | + sample_z = self.model.sample_z( |
| 86 | + self.model.z_mu_context, self.model.z_logvar_context |
| 87 | + ) |
| 88 | + if sample_z.dim() == 1: |
| 89 | + sample_z = sample_z.unsqueeze(0) |
| 90 | + |
| 91 | + y_pred = self.model.decoder(x_i, sample_z) |
| 92 | + |
| 93 | + combined_x = torch.cat([x_c, x_i], dim=0) |
| 94 | + combined_y = torch.cat([y_c, y_pred], dim=0) |
| 95 | + |
| 96 | + self.model.z_mu_all, self.model.z_logvar_all = ( |
| 97 | + self.model.data_to_z_params(combined_x, combined_y) |
| 98 | + ) |
| 99 | + kl_sample = self.model.KLD_gaussian(self.min_std, self.scaler) |
| 100 | + kl_i += kl_sample |
| 101 | + |
| 102 | + kl[i] = kl_i / self.num_samples |
| 103 | + |
| 104 | + else: |
| 105 | + for i in range(N): |
| 106 | + x_i = candidate_x[i] |
| 107 | + kl_i = 0.0 |
| 108 | + for _ in range(self.num_samples): |
| 109 | + posterior_prior = self.model.posterior(self.model.train_inputs[0]) |
| 110 | + posterior_candidate = self.model.posterior(x_i) |
| 111 | + |
| 112 | + mean_prior = posterior_prior.mean.mean(dim=0) |
| 113 | + cov_prior = posterior_prior.variance.mean(dim=0) |
| 114 | + mvn_prior = torch.distributions.MultivariateNormal( |
| 115 | + mean_prior, torch.diag(cov_prior) |
| 116 | + ) |
| 117 | + |
| 118 | + mean_candidate = posterior_candidate.mean.mean(dim=0) |
| 119 | + cov_candidate = posterior_candidate.variance.mean(dim=0) |
| 120 | + mvn_candidate = torch.distributions.MultivariateNormal( |
| 121 | + mean_candidate, torch.diag(cov_candidate) |
| 122 | + ) |
| 123 | + |
| 124 | + kl_i += torch.distributions.kl_divergence(mvn_candidate, mvn_prior) |
| 125 | + |
| 126 | + kl[i] = kl_i / self.num_samples |
| 127 | + |
| 128 | + return kl |
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