prototorch_models/prototorch/models/probabilistic.py

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"""Probabilistic GLVQ methods"""
import torch
from ..core.losses import nllr_loss, rslvq_loss
from ..core.pooling import stratified_min_pooling, stratified_sum_pooling
from ..nn.wrappers import LambdaLayer, LossLayer
from .extras import GaussianPrior, RankScaledGaussianPrior
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from .glvq import GLVQ, SiameseGMLVQ
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class CELVQ(GLVQ):
"""Cross-Entropy Learning Vector Quantization."""
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def __init__(self, hparams, **kwargs):
super().__init__(hparams, **kwargs)
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# Loss
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self.loss = torch.nn.CrossEntropyLoss()
def shared_step(self, batch, batch_idx, optimizer_idx=None):
x, y = batch
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out = self.compute_distances(x) # [None, num_protos]
_, plabels = self.proto_layer()
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winning = stratified_min_pooling(out, plabels) # [None, num_classes]
probs = -1.0 * winning
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batch_loss = self.loss(probs, y.long())
loss = batch_loss.sum()
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return out, loss
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class ProbabilisticLVQ(GLVQ):
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def __init__(self, hparams, rejection_confidence=0.0, **kwargs):
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super().__init__(hparams, **kwargs)
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self.conditional_distribution = None
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self.rejection_confidence = rejection_confidence
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def forward(self, x):
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distances = self.compute_distances(x)
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conditional = self.conditional_distribution(distances)
prior = (1. / self.num_prototypes) * torch.ones(self.num_prototypes,
device=self.device)
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posterior = conditional * prior
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plabels = self.proto_layer._labels
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y_pred = stratified_sum_pooling(posterior, plabels)
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return y_pred
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def predict(self, x):
y_pred = self.forward(x)
confidence, prediction = torch.max(y_pred, dim=1)
prediction[confidence < self.rejection_confidence] = -1
return prediction
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def training_step(self, batch, batch_idx, optimizer_idx=None):
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x, y = batch
out = self.forward(x)
_, plabels = self.proto_layer()
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batch_loss = self.loss(out, y, plabels)
loss = batch_loss.sum()
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return loss
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class SLVQ(ProbabilisticLVQ):
"""Soft Learning Vector Quantization."""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
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self.loss = LossLayer(nllr_loss)
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self.conditional_distribution = GaussianPrior(self.hparams.variance)
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class RSLVQ(ProbabilisticLVQ):
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"""Robust Soft Learning Vector Quantization."""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
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self.loss = LossLayer(rslvq_loss)
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self.conditional_distribution = GaussianPrior(self.hparams.variance)
class PLVQ(ProbabilisticLVQ, SiameseGMLVQ):
"""Probabilistic Learning Vector Quantization.
TODO: Use Backbone LVQ instead
"""
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def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.conditional_distribution = RankScaledGaussianPrior(
self.hparams.lambd)
self.loss = torch.nn.KLDivLoss()
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# FIXME
# def training_step(self, batch, batch_idx, optimizer_idx=None):
# x, y = batch
# y_pred = self(x)
# batch_loss = self.loss(y_pred, y)
# loss = batch_loss.sum()
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# return loss