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-rw-r--r--utils/triplet_loss.py92
1 files changed, 0 insertions, 92 deletions
diff --git a/utils/triplet_loss.py b/utils/triplet_loss.py
deleted file mode 100644
index 5e3a97a..0000000
--- a/utils/triplet_loss.py
+++ /dev/null
@@ -1,92 +0,0 @@
-from typing import Optional
-
-import torch
-import torch.nn as nn
-import torch.nn.functional as F
-
-
-class BatchTripletLoss(nn.Module):
- def __init__(
- self,
- is_hard: bool = True,
- is_mean: bool = True,
- margin: Optional[float] = 0.2,
- ):
- super().__init__()
- self.is_hard = is_hard
- self.is_mean = is_mean
- self.margin = margin
-
- def forward(self, x, y):
- p, n, c = x.size()
- dist = self._batch_distance(x)
- flat_dist_mask = torch.tril_indices(n, n, offset=-1, device=dist.device)
- flat_dist = dist[:, flat_dist_mask[0], flat_dist_mask[1]]
-
- if self.is_hard:
- positive_negative_dist = self._hard_distance(dist, y, p, n)
- else: # is_all
- positive_negative_dist = self._all_distance(dist, y, p, n)
-
- non_zero_counts = None
- if self.margin:
- losses = F.relu(self.margin + positive_negative_dist).view(p, -1)
- non_zero_counts = (losses != 0).sum(1).float()
- if self.is_mean:
- loss_metric = self._none_zero_mean(losses, non_zero_counts)
- else: # is_sum
- loss_metric = losses.sum(1)
- else: # Soft margin
- losses = F.softplus(positive_negative_dist).view(p, -1)
- if self.is_mean:
- loss_metric = losses.mean(1)
- else: # is_sum
- loss_metric = losses.sum(1)
-
- return {
- 'loss': loss_metric,
- 'dist': flat_dist,
- 'counts': non_zero_counts
- }
-
- @staticmethod
- def _batch_distance(x):
- # Euclidean distance p x n x n
- x_squared_sum = torch.sum(x ** 2, dim=2)
- x1_squared_sum = x_squared_sum.unsqueeze(2)
- x2_squared_sum = x_squared_sum.unsqueeze(1)
- x1_times_x2_sum = x @ x.transpose(1, 2)
- dist = torch.sqrt(
- F.relu(x1_squared_sum - 2 * x1_times_x2_sum + x2_squared_sum)
- )
- return dist
-
- @staticmethod
- def _hard_distance(dist, y, p, n):
- positive_mask = y.unsqueeze(1) == y.unsqueeze(2)
- negative_mask = y.unsqueeze(1) != y.unsqueeze(2)
- hard_positive = dist[positive_mask].view(p, n, -1).max(-1).values
- hard_negative = dist[negative_mask].view(p, n, -1).min(-1).values
- positive_negative_dist = hard_positive - hard_negative
-
- return positive_negative_dist
-
- @staticmethod
- def _all_distance(dist, y, p, n):
- # Unmask identical samples
- positive_mask = torch.eye(
- n, dtype=torch.bool, device=y.device
- ) ^ (y.unsqueeze(1) == y.unsqueeze(2))
- negative_mask = y.unsqueeze(1) != y.unsqueeze(2)
- all_positive = dist[positive_mask].view(p, n, -1, 1)
- all_negative = dist[negative_mask].view(p, n, 1, -1)
- positive_negative_dist = all_positive - all_negative
-
- return positive_negative_dist
-
- @staticmethod
- def _none_zero_mean(losses, non_zero_counts):
- # Non-zero parted mean
- non_zero_mean = losses.sum(1) / non_zero_counts
- non_zero_mean[non_zero_counts == 0] = 0
- return non_zero_mean