pytorch-metric-learning 0.9.19

A flexible and extensible metric learning library, written in PyTorch.

pytorch_metric_learning

Coming soon in a separate repo: a highly configurable and easy-to-use benchmarking tool.

Loss functions implemented:

• angular
• contrastive
• lifted structure
• margin
• multi similarity
• n pairs
• nca
• proxy nca
• triplet margin
• more to be added

Mining functions implemented:

• distance weighted sampling
• hard aware cascaded mining
• maximum loss miner
• multi similarity miner
• pair margin miner
• more to be added

Training methods implemented:

• metric loss only
• training with classifier
• cascaded embeddings
• deep adversarial metric learning
• more to be added

Installation:

pip install pytorch_metric_learning

Overview

Use a loss function by itself

from pytorch_metric_learning import losses
loss_func = losses.TripletMarginLoss(normalize_embeddings=False, margin=0.1)
loss = loss_func(embeddings, labels)

Or combine miners and loss functions, regardless of whether they mine or compute loss using pairs or triplets. Pairs are converted to triplets when necessary, and vice versa.

from pytorch_metric_learning import miners, losses
miner = miners.MultiSimilarityMiner(epsilon=0.1)
loss_func = losses.TripletMarginLoss(normalize_embeddings=False, margin=0.1)
hard_pairs = miner(embeddings, labels)
loss = loss_func(embeddings, labels, hard_pairs)

Train using more advanced approaches, like deep adversarial metric learning. For example:

from pytorch_metric_learning import trainers

# Set up your models, optimizers, loss functions etc.
models = {"trunk": your_trunk_model, 
          "embedder": your_embedder_model,
          "G_neg_model": your_negative_generator}

optimizers = {"trunk_optimizer": your_trunk_optimizer, 
              "embedder_optimizer": your_embedder_optimizer,
              "G_neg_model_optimizer": your_negative_generator_optimizer}

loss_funcs = {"metric_loss": losses.AngularNPairs(alpha=35),
              "synth_loss": losses.Angular(alpha=35), 
              "G_neg_adv": losses.Angular(alpha=35)}

mining_funcs = {}

loss_weights = {"metric_loss": 1, 
                "classifier_loss": 0,
                "synth_loss": 0.1,
                "G_neg_adv": 0.1,
                "G_neg_hard": 0.1,
                "G_neg_reg": 0.1}

# Create trainer object
trainer = trainers.DeepAdversarialMetricLearning(
  models=models,
  optimizers=optimizers,
  batch_size=120,
  loss_funcs=loss_funcs,
  mining_funcs=mining_funcs,
  num_epochs=50,
  iterations_per_epoch=100,
  dataset=your_dataset,
  loss_weights=loss_weights
)

# Train!
trainer.train()