feat: add longclip

src/open_clip/loss.py

@@ -1,6 +1,7 @@
 import torch
 import torch.nn as nn
 from torch.nn import functional as F
+from typing import Optional
 
 try:
     import torch.distributed.nn
@@ -16,6 +17,7 @@
 except ImportError:
     hvd = None
 
+from utils import PCA
 
 class GatherFeatures:
 
@@ -39,7 +41,7 @@ def __init__(
         if use_horovod:
             assert hvd is not None, 'Please install horovod'
 
-    def __call__(self, features: torch.Tensor):
+    def __call__(self, features: torch.Tensor, pca_dim: Optional[int] = None):
         if self.use_horovod:
             if self.gather_with_grad:
                 all_features = hvd.allgather(features)
@@ -70,7 +72,8 @@ def __call__(self, features: torch.Tensor):
                     gathered_features[self.rank] = features
 
                 all_features = torch.cat(gathered_features, dim=0)
-
+        if pca_dim:
+            all_features = PCA(all_features)
         return all_features
 
 
@@ -84,17 +87,19 @@ def gather_features(
     rank=0,
     world_size=1,
     use_horovod=False,
+    pca_dim=None
 ):
     gather = GatherFeatures(
         local_loss=local_loss,
         gather_with_grad=gather_with_grad,
         rank=rank,
         world_size=world_size,
         use_horovod=use_horovod,
+        pca_dim=pca_dim,
     )
     return (
-        gather(image_features),
-        gather(text_features),
+        gather(image_features, pca_dim=pca_dim), # apply PCA on image faetures if set
+        gather(text_features, pca_dim=None), # never apply PCA on text features
         gather(teacher_features) if teacher_features else None
     )
 
@@ -134,7 +139,7 @@ def get_ground_truth(self, device, num_logits) -> torch.Tensor:
             labels = self.labels[device]
         return labels
 
-    def get_logits(self, image_features, text_features, logit_scale):
+    def get_logits(self, image_features, text_features, logit_scale, pca_dim: Optional[int] = None):
         if self.world_size > 1:
             all_image_features, all_text_features, _ = gather_features(
                 image_features=image_features,
@@ -144,6 +149,7 @@ def get_logits(self, image_features, text_features, logit_scale):
                 rank=self.rank,
                 world_size=self.world_size,
                 use_horovod=self.use_horovod,
+                pca_dim=pca_dim
             )
             if self.local_loss:
                 logits_per_image = logit_scale * image_features @ all_text_features.T
@@ -154,15 +160,17 @@ def get_logits(self, image_features, text_features, logit_scale):
                 )
                 logits_per_text = logits_per_image.T
         else:
+            if pca_dim:
+                image_features = PCA(image_features)
             logits_per_image = logit_scale * image_features @ text_features.T
             logits_per_text = logit_scale * text_features @ image_features.T
 
         return logits_per_image, logits_per_text
 
-    def forward(self, image_features, text_features, logit_scale, output_dict=False):
+    def forward(self, image_features, text_features, logit_scale, output_dict=False, pca_dim = None):
         device = image_features.device
         logits_per_image, logits_per_text = self.get_logits(
-            image_features, text_features, logit_scale
+            image_features, text_features, logit_scale, pca_dim,
         )
 
         labels = self.get_ground_truth(device, logits_per_image.shape[0])

src/open_clip/utils.py

@@ -6,6 +6,24 @@
 from torchvision.ops.misc import FrozenBatchNorm2d
 
 
+def PCA(input_tensor, PCA_dim):
+    mean = torch.mean(input_tensor, dim=0)
+    X_centered = input_tensor - mean.unsqueeze(0)
+    X_centered = X_centered.float()
+    cov_matrix = torch.mm(X_centered.T, X_centered)
+    eigenvalues, eigenvectors = torch.linalg.eig(cov_matrix)
+    eigenvalues = eigenvalues.float()
+    eigenvectors = eigenvectors.float()    
+    sorted_indices = torch.argsort(eigenvalues, descending=True)
+    eigenvectors = eigenvectors[:, sorted_indices]
+    principal_components = eigenvectors[:, :PCA_dim]
+    X_transformed = torch.mm(X_centered, principal_components)
+    X_reversed = torch.mm(X_transformed, principal_components.T)
+    X_reversed += mean
+    return X_reversed
+
+
+
 def freeze_batch_norm_2d(module, module_match={}, name=''):
     """
     Converts all `BatchNorm2d` and `SyncBatchNorm` layers of provided module into `FrozenBatchNorm2d`. If `module` is

src/training/train.py

@@ -143,6 +143,11 @@ def train_one_epoch(
         images, texts = mm_batch
         images = images.to(device=device, dtype=input_dtype, non_blocking=True)
         texts = texts.to(device=device, non_blocking=True)
+        if args.longclip:
+            images_short = images.clone()
+            texts_short = []
+            for text in texts:
+                texts_short.append(text.split(". ")[0])
         if emb_batch:
             for batch in emb_batch:
                 batch.to(device=device)
@@ -200,6 +205,9 @@ def train_one_epoch(
 
                     losses['embedding_loss'] = args.emb_loss_weight * embedding_loss
 
+                if args.longclip:
+                    modelout_short = model(images_short, texts_short)
+                    loss_short = loss(**modelout_short, output_dict=True, pca_dim=32)
             total_loss = sum(losses.values())
             losses['loss'] = total_loss
             backward(total_loss, model, scaler=scaler, deepspeed=args.deepspeed)