"""Models based on the GLVQ framework.""" import torch from prototorch.core.competitions import wtac from prototorch.core.distances import ( lomega_distance, omega_distance, squared_euclidean_distance, ) from prototorch.core.initializers import EyeLinearTransformInitializer from prototorch.core.losses import ( GLVQLoss, lvq1_loss, lvq21_loss, ) from prototorch.core.transforms import LinearTransform from prototorch.nn.wrappers import LambdaLayer, LossLayer from torch.nn.parameter import Parameter from .abstract import ImagePrototypesMixin, SupervisedPrototypeModel from .extras import ltangent_distance, orthogonalization class GLVQ(SupervisedPrototypeModel): """Generalized Learning Vector Quantization.""" def __init__(self, hparams, **kwargs): super().__init__(hparams, **kwargs) # Default hparams self.hparams.setdefault("margin", 0.0) self.hparams.setdefault("transfer_fn", "identity") self.hparams.setdefault("transfer_beta", 10.0) # Loss self.loss = GLVQLoss( margin=self.hparams["margin"], transfer_fn=self.hparams["transfer_fn"], beta=self.hparams["transfer_beta"], ) # def on_save_checkpoint(self, checkpoint): # if "prototype_win_ratios" in checkpoint["state_dict"]: # del checkpoint["state_dict"]["prototype_win_ratios"] def initialize_prototype_win_ratios(self): self.register_buffer( "prototype_win_ratios", torch.zeros(self.num_prototypes, device=self.device)) def on_train_epoch_start(self): self.initialize_prototype_win_ratios() def log_prototype_win_ratios(self, distances): batch_size = len(distances) prototype_wc = torch.zeros(self.num_prototypes, dtype=torch.long, device=self.device) wi, wc = torch.unique(distances.min(dim=-1).indices, sorted=True, return_counts=True) prototype_wc[wi] = wc prototype_wr = prototype_wc / batch_size self.prototype_win_ratios = torch.vstack([ self.prototype_win_ratios, prototype_wr, ]) def shared_step(self, batch, batch_idx, optimizer_idx=None): x, y = batch out = self.compute_distances(x) _, plabels = self.proto_layer() loss = self.loss(out, y, plabels) return out, loss def training_step(self, batch, batch_idx, optimizer_idx=None): out, train_loss = self.shared_step(batch, batch_idx, optimizer_idx) self.log_prototype_win_ratios(out) self.log("train_loss", train_loss) self.log_acc(out, batch[-1], tag="train_acc") return train_loss def validation_step(self, batch, batch_idx): # `model.eval()` and `torch.no_grad()` handled by pl out, val_loss = self.shared_step(batch, batch_idx) self.log("val_loss", val_loss) self.log_acc(out, batch[-1], tag="val_acc") return val_loss def test_step(self, batch, batch_idx): # `model.eval()` and `torch.no_grad()` handled by pl out, test_loss = self.shared_step(batch, batch_idx) self.log_acc(out, batch[-1], tag="test_acc") return test_loss def test_epoch_end(self, outputs): test_loss = 0.0 for batch_loss in outputs: test_loss += batch_loss.item() self.log("test_loss", test_loss) # TODO # def predict_step(self, batch, batch_idx, dataloader_idx=None): # pass class SiameseGLVQ(GLVQ): """GLVQ in a Siamese setting. GLVQ model that applies an arbitrary transformation on the inputs and the prototypes before computing the distances between them. The weights in the transformation pipeline are only learned from the inputs. """ def __init__(self, hparams, backbone=torch.nn.Identity(), both_path_gradients=False, **kwargs): distance_fn = kwargs.pop("distance_fn", squared_euclidean_distance) super().__init__(hparams, distance_fn=distance_fn, **kwargs) self.backbone = backbone self.both_path_gradients = both_path_gradients def compute_distances(self, x): protos, _ = self.proto_layer() x, protos = (arr.view(arr.size(0), -1) for arr in (x, protos)) latent_x = self.backbone(x) bb_grad = any([el.requires_grad for el in self.backbone.parameters()]) self.backbone.requires_grad_(bb_grad and self.both_path_gradients) latent_protos = self.backbone(protos) self.backbone.requires_grad_(bb_grad) distances = self.distance_layer(latent_x, latent_protos) return distances def predict_latent(self, x, map_protos=True): """Predict `x` assuming it is already embedded in the latent space. Only the prototypes are embedded in the latent space using the backbone. """ self.eval() with torch.no_grad(): protos, plabels = self.proto_layer() if map_protos: protos = self.backbone(protos) d = self.distance_layer(x, protos) y_pred = wtac(d, plabels) return y_pred class LVQMLN(SiameseGLVQ): """Learning Vector Quantization Multi-Layer Network. GLVQ model that applies an arbitrary transformation on the inputs, BUT NOT on the prototypes before computing the distances between them. This of course, means that the prototypes no longer live the input space, but rather in the embedding space. """ def compute_distances(self, x): latent_protos, _ = self.proto_layer() latent_x = self.backbone(x) distances = self.distance_layer(latent_x, latent_protos) return distances class GRLVQ(SiameseGLVQ): """Generalized Relevance Learning Vector Quantization. Implemented as a Siamese network with a linear transformation backbone. TODO Make a RelevanceLayer. `bb_lr` is ignored otherwise. """ _relevances: torch.Tensor def __init__(self, hparams, **kwargs): super().__init__(hparams, **kwargs) # Additional parameters relevances = torch.ones(self.hparams["input_dim"], device=self.device) self.register_parameter("_relevances", Parameter(relevances)) # Override the backbone self.backbone = LambdaLayer(self._apply_relevances, name="relevance scaling") def _apply_relevances(self, x): return x @ torch.diag(self._relevances) @property def relevance_profile(self): return self._relevances.detach().cpu() def extra_repr(self): return f"(relevances): (shape: {tuple(self._relevances.shape)})" class SiameseGMLVQ(SiameseGLVQ): """Generalized Matrix Learning Vector Quantization. Implemented as a Siamese network with a linear transformation backbone. """ def __init__(self, hparams, **kwargs): super().__init__(hparams, **kwargs) # Override the backbone omega_initializer = kwargs.get("omega_initializer", EyeLinearTransformInitializer()) self.backbone = LinearTransform( self.hparams["input_dim"], self.hparams["latent_dim"], initializer=omega_initializer, ) @property def omega_matrix(self): return self.backbone.weights @property def lambda_matrix(self): omega = self.backbone.weights # (input_dim, latent_dim) lam = omega @ omega.T return lam.detach().cpu() class GMLVQ(GLVQ): """Generalized Matrix Learning Vector Quantization. Implemented as a regular GLVQ network that simply uses a different distance function. This makes it easier to implement a localized variant. """ # Parameters _omega: torch.Tensor def __init__(self, hparams, **kwargs): distance_fn = kwargs.pop("distance_fn", omega_distance) super().__init__(hparams, distance_fn=distance_fn, **kwargs) # Additional parameters omega_initializer = kwargs.get("omega_initializer", EyeLinearTransformInitializer()) omega = omega_initializer.generate(self.hparams["input_dim"], self.hparams["latent_dim"]) self.register_parameter("_omega", Parameter(omega)) @property def omega_matrix(self): return self._omega.detach().cpu() @property def lambda_matrix(self): omega = self._omega.detach() # (input_dim, latent_dim) lam = omega @ omega.T return lam.detach().cpu() def compute_distances(self, x): protos, _ = self.proto_layer() distances = self.distance_layer(x, protos, self._omega) return distances def extra_repr(self): return f"(omega): (shape: {tuple(self._omega.shape)})" class LGMLVQ(GMLVQ): """Localized and Generalized Matrix Learning Vector Quantization.""" def __init__(self, hparams, **kwargs): distance_fn = kwargs.pop("distance_fn", lomega_distance) super().__init__(hparams, distance_fn=distance_fn, **kwargs) # Re-register `_omega` to override the one from the super class. omega = torch.randn( self.num_prototypes, self.hparams["input_dim"], self.hparams["latent_dim"], device=self.device, ) self.register_parameter("_omega", Parameter(omega)) class GTLVQ(LGMLVQ): """Localized and Generalized Tangent Learning Vector Quantization.""" def __init__(self, hparams, **kwargs): distance_fn = kwargs.pop("distance_fn", ltangent_distance) super().__init__(hparams, distance_fn=distance_fn, **kwargs) omega_initializer = kwargs.get("omega_initializer") if omega_initializer is not None: subspace = omega_initializer.generate( self.hparams["input_dim"], self.hparams["latent_dim"], ) omega = torch.repeat_interleave( subspace.unsqueeze(0), self.num_prototypes, dim=0, ) else: omega = torch.rand( self.num_prototypes, self.hparams["input_dim"], self.hparams["latent_dim"], device=self.device, ) # Re-register `_omega` to override the one from the super class. self.register_parameter("_omega", Parameter(omega)) def on_train_batch_end(self, outputs, batch, batch_idx): with torch.no_grad(): self._omega.copy_(orthogonalization(self._omega)) class SiameseGTLVQ(SiameseGLVQ, GTLVQ): """Generalized Tangent Learning Vector Quantization. Implemented as a Siamese network with a linear transformation backbone. """ class GLVQ1(GLVQ): """Generalized Learning Vector Quantization 1.""" def __init__(self, hparams, **kwargs): super().__init__(hparams, **kwargs) self.loss = LossLayer(lvq1_loss) self.optimizer = torch.optim.SGD class GLVQ21(GLVQ): """Generalized Learning Vector Quantization 2.1.""" def __init__(self, hparams, **kwargs): super().__init__(hparams, **kwargs) self.loss = LossLayer(lvq21_loss) self.optimizer = torch.optim.SGD class ImageGLVQ(ImagePrototypesMixin, GLVQ): """GLVQ for training on image data. GLVQ model that constrains the prototypes to the range [0, 1] by clamping after updates. """ class ImageGMLVQ(ImagePrototypesMixin, GMLVQ): """GMLVQ for training on image data. GMLVQ model that constrains the prototypes to the range [0, 1] by clamping after updates. """ class ImageGTLVQ(ImagePrototypesMixin, GTLVQ): """GTLVQ for training on image data. GTLVQ model that constrains the prototypes to the range [0, 1] by clamping after updates. """ def on_train_batch_end(self, outputs, batch, batch_idx): """Constrain the components to the range [0, 1] by clamping after updates.""" self.proto_layer.components.data.clamp_(0.0, 1.0) with torch.no_grad(): self._omega.copy_(orthogonalization(self._omega))