prototorch_models/prototorch/models/cbc.py
2021-06-01 23:39:39 +02:00

156 lines
5.4 KiB
Python

import pytorch_lightning as pl
import torch
import torchmetrics
from prototorch.components.components import Components
from prototorch.functions.distances import euclidean_distance
from prototorch.functions.similarities import cosine_similarity
from .abstract import AbstractPrototypeModel, PrototypeImageModel
from .glvq import SiameseGLVQ
def rescaled_cosine_similarity(x, y):
"""Cosine Similarity rescaled to [0, 1]."""
similarities = cosine_similarity(x, y)
return (similarities + 1.0) / 2.0
def shift_activation(x):
return (x + 1.0) / 2.0
def euclidean_similarity(x, y, beta=3):
d = euclidean_distance(x, y)
return torch.exp(-d * beta)
class CosineSimilarity(torch.nn.Module):
def __init__(self, activation=shift_activation):
super().__init__()
self.activation = activation
def forward(self, x, y):
epsilon = torch.finfo(x.dtype).eps
normed_x = (x / x.pow(2).sum(dim=tuple(range(
1, x.ndim)), keepdim=True).clamp(min=epsilon).sqrt()).flatten(
start_dim=1)
normed_y = (y / y.pow(2).sum(dim=tuple(range(
1, y.ndim)), keepdim=True).clamp(min=epsilon).sqrt()).flatten(
start_dim=1)
# normed_x = (x / torch.linalg.norm(x, dim=1))
diss = torch.inner(normed_x, normed_y)
return self.activation(diss)
class MarginLoss(torch.nn.modules.loss._Loss):
def __init__(self,
margin=0.3,
size_average=None,
reduce=None,
reduction="mean"):
super().__init__(size_average, reduce, reduction)
self.margin = margin
def forward(self, input_, target):
dp = torch.sum(target * input_, dim=-1)
dm = torch.max(input_ - target, dim=-1).values
return torch.nn.functional.relu(dm - dp + self.margin)
class ReasoningLayer(torch.nn.Module):
def __init__(self, num_components, num_classes, num_replicas=1):
super().__init__()
self.num_replicas = num_replicas
self.num_classes = num_classes
probabilities_init = torch.zeros(2, 1, num_components,
self.num_classes)
probabilities_init.uniform_(0.4, 0.6)
self.reasoning_probabilities = torch.nn.Parameter(probabilities_init)
@property
def reasonings(self):
pk = self.reasoning_probabilities[0]
nk = (1 - pk) * self.reasoning_probabilities[1]
ik = 1 - pk - nk
img = torch.cat([pk, nk, ik], dim=0).permute(1, 0, 2)
return img.unsqueeze(1)
def forward(self, detections):
pk = self.reasoning_probabilities[0].clamp(0, 1)
nk = (1 - pk) * self.reasoning_probabilities[1].clamp(0, 1)
numerator = (detections @ (pk - nk)) + nk.sum(1)
probs = numerator / (pk + nk).sum(1)
probs = probs.squeeze(0)
return probs
class CBC(SiameseGLVQ):
"""Classification-By-Components."""
def __init__(self,
hparams,
margin=0.1,
similarity=euclidean_similarity,
**kwargs):
super().__init__(hparams, **kwargs)
self.margin = margin
self.similarity_fn = kwargs.get("similarity_fn", euclidean_similarity)
num_components = self.components.shape[0]
self.reasoning_layer = ReasoningLayer(num_components=num_components,
num_classes=self.num_classes)
self.component_layer = self.proto_layer
@property
def components(self):
return self.prototypes
@property
def reasonings(self):
return self.reasoning_layer.reasonings.cpu()
def forward(self, x):
components, _ = self.component_layer()
latent_x = self.backbone(x)
self.backbone.requires_grad_(self.both_path_gradients)
latent_components = self.backbone(components)
self.backbone.requires_grad_(True)
detections = self.similarity_fn(latent_x, latent_components)
probs = self.reasoning_layer(detections)
return probs
def shared_step(self, batch, batch_idx, optimizer_idx=None):
x, y = batch
# x = x.view(x.size(0), -1)
y_pred = self(x)
num_classes = self.reasoning_layer.num_classes
y_true = torch.nn.functional.one_hot(y.long(), num_classes=num_classes)
loss = MarginLoss(self.margin)(y_pred, y_true).mean(dim=0)
return y_pred, loss
def training_step(self, batch, batch_idx, optimizer_idx=None):
y_pred, train_loss = self.shared_step(batch, batch_idx, optimizer_idx)
preds = torch.argmax(y_pred, dim=1)
accuracy = torchmetrics.functional.accuracy(preds.int(),
batch[1].int())
self.log("train_acc",
accuracy,
on_step=False,
on_epoch=True,
prog_bar=True,
logger=True)
return train_loss
def predict(self, x):
with torch.no_grad():
y_pred = self(x)
y_pred = torch.argmax(y_pred, dim=1)
return y_pred
class ImageCBC(CBC):
"""CBC model that constrains the components to the range [0, 1] by
clamping after updates.
"""
def on_train_batch_end(self, outputs, batch, batch_idx, dataloader_idx):
# super().on_train_batch_end(outputs, batch, batch_idx, dataloader_idx)
self.component_layer.components.data.clamp_(0.0, 1.0)