|
| 1 | +import torch |
| 2 | +import pyro.contrib.gp as gp |
| 3 | +import pyro.distributions as dist |
| 4 | +import numpy as np |
| 5 | + |
| 6 | +from naslib.predictors.gp_base import BaseGPModel |
| 7 | +from naslib.utils.utils import AverageMeterGroup, TensorDatasetWithTrans |
| 8 | + |
| 9 | +device = torch.device('cpu') #NOTE: faster on CPU |
| 10 | + |
| 11 | +# TODO |
| 12 | + |
| 13 | +class DeepVarSparseGP(pyro.nn.PyroModule): |
| 14 | + def __init__(self, X, y, Xu, mean_fn): |
| 15 | + super(DeepVarSparseGP, self).__init__() |
| 16 | + self.layer1 = gp.models.VariationalSparseGP( |
| 17 | + X, |
| 18 | + None, |
| 19 | + gp.kernels.RBF(X.shape[1], variance=torch.tensor(5.).double(), |
| 20 | + lengthscale=torch.tensor(10.).double()), |
| 21 | + Xu=Xu, |
| 22 | + likelihood=None, |
| 23 | + mean_function=mean_fn, |
| 24 | + latent_shape=torch.Size([10])) |
| 25 | + |
| 26 | + h = mean_fn(X).t() |
| 27 | + hu = mean_fn(Xu).t() |
| 28 | + self.layer2 = gp.models.VariationalSparseGP( |
| 29 | + h, |
| 30 | + y, |
| 31 | + gp.kernels.RBF(10, variance=torch.tensor(5.).double(), |
| 32 | + lengthscale=torch.tensor(10.).double()), |
| 33 | + Xu=hu, |
| 34 | + likelihood=gp.likelihoods.Gaussian(), |
| 35 | + latent_shape=torch.Size([1])) |
| 36 | + |
| 37 | + def model(self, X, y): |
| 38 | + self.layer1.set_data(X, None) |
| 39 | + h_loc, h_var = self.layer1.model() |
| 40 | + # approximate with MC sample |
| 41 | + h = dist.Normal(h_loc, h_var.sqrt())() |
| 42 | + self.layer2.set_data(h.t(), y) |
| 43 | + self.layer2.model() |
| 44 | + |
| 45 | + def guide(self, X, y): |
| 46 | + self.layer1.guide() |
| 47 | + self.layer2.guide() |
| 48 | + |
| 49 | + # make predictions |
| 50 | + def forward(self, X_new): |
| 51 | + # because prediction is stochastic (due to Monte Carlo sample of hidden layer), |
| 52 | + # we make 100 prediction and take the most common one |
| 53 | + pred = [] |
| 54 | + for _ in range(100): |
| 55 | + h_loc, h_var = self.layer1(X_new) |
| 56 | + h = dist.Normal(h_loc, h_var.sqrt())() |
| 57 | + f_loc, f_var = self.layer2(h.t()) |
| 58 | + pred.append(f_loc.argmax(dim=0)) |
| 59 | + return torch.stack(pred).mode(dim=0)[0] |
| 60 | + |
| 61 | + |
| 62 | +class DeepVarSparseGPPredictor(BaseGPModel): |
| 63 | + |
| 64 | + def get_dataset(self, encodings, labels=None): |
| 65 | + if labels is None: |
| 66 | + return torch.tensor(encodings).double() |
| 67 | + else: |
| 68 | + return (torch.tensor(encodings).double(), |
| 69 | + torch.tensor((labels-self.mean)/self.std).double()) |
| 70 | + X_tensor = torch.FloatTensor(_xtrain).to(device) |
| 71 | + y_tensor = torch.FloatTensor(_ytrain).to(device) |
| 72 | + |
| 73 | + train_data = TensorDataset(X_tensor, y_tensor) |
| 74 | + |
| 75 | + def get_model(self, train_data, **kwargs): |
| 76 | + deepgp = DeepVarSparseGP( |
| 77 | + |
| 78 | + def train(self, train_data, optimize_gp_hyper=False): |
| 79 | + X_train, y_train = train_data |
| 80 | + # initialize the kernel and model |
| 81 | + pyro.clear_param_store() |
| 82 | + kernel = self.kernel(input_dim=X_train.shape[1]) |
| 83 | + Xu = torch.arange(10.) / 2.0 |
| 84 | + Xu.unsqueeze_(-1) |
| 85 | + Xu = Xu.expand(10, X_train.shape[1]).double() |
| 86 | + likelihood = gp.likelihoods.Gaussian() |
| 87 | + self.gpr = gp.models.VariationalSparseGP(X_train, y_train, kernel, |
| 88 | + Xu=Xu, likelihood=likelihood, |
| 89 | + whiten=True) |
| 90 | + |
| 91 | + return self.gpr |
| 92 | + |
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