307 lines
10 KiB
Python
307 lines
10 KiB
Python
"""Models based on the GLVQ framework."""
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import torch
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from torch.nn.parameter import Parameter
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from ..core.competitions import wtac
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from ..core.distances import lomega_distance, omega_distance, squared_euclidean_distance
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from ..core.initializers import EyeTransformInitializer
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from ..core.losses import glvq_loss, lvq1_loss, lvq21_loss
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from ..nn.activations import get_activation
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from ..nn.wrappers import LambdaLayer, LossLayer
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from .abstract import ImagePrototypesMixin, SupervisedPrototypeModel
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class GLVQ(SupervisedPrototypeModel):
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"""Generalized Learning Vector Quantization."""
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def __init__(self, hparams, **kwargs):
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super().__init__(hparams, **kwargs)
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# Default hparams
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self.hparams.setdefault("transfer_fn", "identity")
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self.hparams.setdefault("transfer_beta", 10.0)
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# Layers
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transfer_fn = get_activation(self.hparams.transfer_fn)
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self.transfer_layer = LambdaLayer(transfer_fn)
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# Loss
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self.loss = LossLayer(glvq_loss)
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def initialize_prototype_win_ratios(self):
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self.register_buffer(
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"prototype_win_ratios",
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torch.zeros(self.num_prototypes, device=self.device))
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def on_epoch_start(self):
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self.initialize_prototype_win_ratios()
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def log_prototype_win_ratios(self, distances):
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batch_size = len(distances)
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prototype_wc = torch.zeros(self.num_prototypes,
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dtype=torch.long,
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device=self.device)
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wi, wc = torch.unique(distances.min(dim=-1).indices,
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sorted=True,
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return_counts=True)
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prototype_wc[wi] = wc
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prototype_wr = prototype_wc / batch_size
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self.prototype_win_ratios = torch.vstack([
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self.prototype_win_ratios,
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prototype_wr,
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])
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def shared_step(self, batch, batch_idx, optimizer_idx=None):
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x, y = batch
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out = self.compute_distances(x)
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plabels = self.proto_layer.labels
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mu = self.loss(out, y, prototype_labels=plabels)
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batch_loss = self.transfer_layer(mu, beta=self.hparams.transfer_beta)
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loss = batch_loss.sum(dim=0)
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return out, loss
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def training_step(self, batch, batch_idx, optimizer_idx=None):
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out, train_loss = self.shared_step(batch, batch_idx, optimizer_idx)
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self.log_prototype_win_ratios(out)
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self.log("train_loss", train_loss)
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self.log_acc(out, batch[-1], tag="train_acc")
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return train_loss
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def validation_step(self, batch, batch_idx):
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# `model.eval()` and `torch.no_grad()` handled by pl
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out, val_loss = self.shared_step(batch, batch_idx)
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self.log("val_loss", val_loss)
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self.log_acc(out, batch[-1], tag="val_acc")
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return val_loss
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def test_step(self, batch, batch_idx):
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# `model.eval()` and `torch.no_grad()` handled by pl
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out, test_loss = self.shared_step(batch, batch_idx)
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self.log_acc(out, batch[-1], tag="test_acc")
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return test_loss
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def test_epoch_end(self, outputs):
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test_loss = 0.0
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for batch_loss in outputs:
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test_loss += batch_loss.item()
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self.log("test_loss", test_loss)
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# TODO
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# def predict_step(self, batch, batch_idx, dataloader_idx=None):
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# pass
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class SiameseGLVQ(GLVQ):
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"""GLVQ in a Siamese setting.
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GLVQ model that applies an arbitrary transformation on the inputs and the
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prototypes before computing the distances between them. The weights in the
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transformation pipeline are only learned from the inputs.
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"""
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def __init__(self,
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hparams,
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backbone=torch.nn.Identity(),
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both_path_gradients=False,
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**kwargs):
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distance_fn = kwargs.pop("distance_fn", squared_euclidean_distance)
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super().__init__(hparams, distance_fn=distance_fn, **kwargs)
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self.backbone = backbone
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self.both_path_gradients = both_path_gradients
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def configure_optimizers(self):
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proto_opt = self.optimizer(self.proto_layer.parameters(),
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lr=self.hparams.proto_lr)
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# Only add a backbone optimizer if backbone has trainable parameters
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if (bb_params := list(self.backbone.parameters())):
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bb_opt = self.optimizer(bb_params, lr=self.hparams.bb_lr)
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optimizers = [proto_opt, bb_opt]
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else:
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optimizers = [proto_opt]
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if self.lr_scheduler is not None:
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schedulers = []
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for optimizer in optimizers:
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scheduler = self.lr_scheduler(optimizer,
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**self.lr_scheduler_kwargs)
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schedulers.append(scheduler)
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return optimizers, schedulers
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else:
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return optimizers
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def compute_distances(self, x):
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protos, _ = self.proto_layer()
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x, protos = [arr.view(arr.size(0), -1) for arr in (x, protos)]
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latent_x = self.backbone(x)
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self.backbone.requires_grad_(self.both_path_gradients)
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latent_protos = self.backbone(protos)
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self.backbone.requires_grad_(True)
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distances = self.distance_layer(latent_x, latent_protos)
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return distances
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def predict_latent(self, x, map_protos=True):
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"""Predict `x` assuming it is already embedded in the latent space.
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Only the prototypes are embedded in the latent space using the
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backbone.
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"""
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self.eval()
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with torch.no_grad():
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protos, plabels = self.proto_layer()
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if map_protos:
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protos = self.backbone(protos)
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d = self.distance_layer(x, protos)
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y_pred = wtac(d, plabels)
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return y_pred
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class LVQMLN(SiameseGLVQ):
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"""Learning Vector Quantization Multi-Layer Network.
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GLVQ model that applies an arbitrary transformation on the inputs, BUT NOT
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on the prototypes before computing the distances between them. This of
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course, means that the prototypes no longer live the input space, but
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rather in the embedding space.
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"""
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def compute_distances(self, x):
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latent_protos, _ = self.proto_layer()
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latent_x = self.backbone(x)
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distances = self.distance_layer(latent_x, latent_protos)
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return distances
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class GRLVQ(SiameseGLVQ):
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"""Generalized Relevance Learning Vector Quantization.
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Implemented as a Siamese network with a linear transformation backbone.
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TODO Make a RelevanceLayer. `bb_lr` is ignored otherwise.
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"""
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def __init__(self, hparams, **kwargs):
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super().__init__(hparams, **kwargs)
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# Additional parameters
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relevances = torch.ones(self.hparams.input_dim, device=self.device)
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self.register_parameter("_relevances", Parameter(relevances))
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# Override the backbone
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self.backbone = LambdaLayer(lambda x: x @ torch.diag(self._relevances),
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name="relevance scaling")
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@property
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def relevance_profile(self):
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return self._relevances.detach().cpu()
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def extra_repr(self):
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return f"(relevances): (shape: {tuple(self._relevances.shape)})"
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class SiameseGMLVQ(SiameseGLVQ):
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"""Generalized Matrix Learning Vector Quantization.
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Implemented as a Siamese network with a linear transformation backbone.
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"""
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def __init__(self, hparams, **kwargs):
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super().__init__(hparams, **kwargs)
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# Override the backbone
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self.backbone = torch.nn.Linear(self.hparams.input_dim,
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self.hparams.latent_dim,
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bias=False)
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@property
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def omega_matrix(self):
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return self.backbone.weight.detach().cpu()
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@property
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def lambda_matrix(self):
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omega = self.backbone.weight # (latent_dim, input_dim)
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lam = omega.T @ omega
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return lam.detach().cpu()
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class GMLVQ(GLVQ):
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"""Generalized Matrix Learning Vector Quantization.
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Implemented as a regular GLVQ network that simply uses a different distance
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function. This makes it easier to implement a localized variant.
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"""
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def __init__(self, hparams, **kwargs):
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distance_fn = kwargs.pop("distance_fn", omega_distance)
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super().__init__(hparams, distance_fn=distance_fn, **kwargs)
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# Additional parameters
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omega_initializer = kwargs.get("omega_initializer",
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EyeTransformInitializer())
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omega = omega_initializer.generate(self.hparams.input_dim,
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self.hparams.latent_dim)
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self.register_parameter("_omega", Parameter(omega))
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self.backbone = LambdaLayer(lambda x: x @ self._omega,
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name="omega matrix")
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@property
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def omega_matrix(self):
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return self._omega.detach().cpu()
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def compute_distances(self, x):
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protos, _ = self.proto_layer()
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distances = self.distance_layer(x, protos, self._omega)
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return distances
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def extra_repr(self):
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return f"(omega): (shape: {tuple(self._omega.shape)})"
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class LGMLVQ(GMLVQ):
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"""Localized and Generalized Matrix Learning Vector Quantization."""
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def __init__(self, hparams, **kwargs):
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distance_fn = kwargs.pop("distance_fn", lomega_distance)
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super().__init__(hparams, distance_fn=distance_fn, **kwargs)
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# Re-register `_omega` to override the one from the super class.
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omega = torch.randn(
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self.num_prototypes,
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self.hparams.input_dim,
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self.hparams.latent_dim,
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device=self.device,
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)
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self.register_parameter("_omega", Parameter(omega))
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class GLVQ1(GLVQ):
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"""Generalized Learning Vector Quantization 1."""
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def __init__(self, hparams, **kwargs):
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super().__init__(hparams, **kwargs)
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self.loss = LossLayer(lvq1_loss)
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self.optimizer = torch.optim.SGD
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class GLVQ21(GLVQ):
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"""Generalized Learning Vector Quantization 2.1."""
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def __init__(self, hparams, **kwargs):
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super().__init__(hparams, **kwargs)
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self.loss = LossLayer(lvq21_loss)
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self.optimizer = torch.optim.SGD
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class ImageGLVQ(ImagePrototypesMixin, GLVQ):
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"""GLVQ for training on image data.
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GLVQ model that constrains the prototypes to the range [0, 1] by clamping
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after updates.
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"""
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class ImageGMLVQ(ImagePrototypesMixin, GMLVQ):
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"""GMLVQ for training on image data.
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GMLVQ model that constrains the prototypes to the range [0, 1] by clamping
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after updates.
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"""
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