Support dynamic_resize in eva.py models

Author: rwightman

timm/layers/pos_embed_sincos.py

@@ -400,13 +400,12 @@ def __init__(
                     temperature=temperature,
                     step=1,
                 )
-                print(bands)
             self.register_buffer(
                 'bands',
                 bands,
                 persistent=False,
             )
-            self.embed = None
+            self.pos_embed = None
         else:
             # cache full sin/cos embeddings if shape provided up front
             embeds = build_rotary_pos_embed(
@@ -425,17 +424,19 @@ def __init__(
             )
 
     def get_embed(self, shape: Optional[List[int]] = None):
-        if self.bands is not None:
+        if self.bands is not None and shape is not None:
             # rebuild embeddings every call, use if target shape changes
-            _assert(shape is not None, 'valid shape needed')
             embeds = build_rotary_pos_embed(
                 shape,
                 self.bands,
                 in_pixels=self.in_pixels,
+                ref_feat_shape=self.ref_feat_shape,
             )
             return torch.cat(embeds, -1)
-        else:
+        elif self.pos_embed is not None:
             return self.pos_embed
+        else:
+            assert False, "get_embed() requires pre-computed pos_embed or valid shape w/ pre-computed bands"
 
     def forward(self, x):
         # assuming channel-first tensor where spatial dim are >= 2

timm/models/eva.py

@@ -367,6 +367,7 @@ def __init__(
             use_abs_pos_emb: bool = True,
             use_rot_pos_emb: bool = False,
             use_post_norm: bool = False,
+            dynamic_size: bool = False,
             ref_feat_shape: Optional[Union[Tuple[int, int], int]] = None,
             head_init_scale: float = 0.001,
     ):
@@ -406,13 +407,19 @@ def __init__(
         self.global_pool = global_pool
         self.num_features = self.embed_dim = embed_dim  # num_features for consistency with other models
         self.num_prefix_tokens = 1 if class_token else 0
+        self.dynamic_size = dynamic_size
         self.grad_checkpointing = False
 
+        embed_args = {}
+        if dynamic_size:
+            # flatten deferred until after pos embed
+            embed_args.update(dict(strict_img_size=False, output_fmt='NHWC'))
         self.patch_embed = PatchEmbed(
             img_size=img_size,
             patch_size=patch_size,
             in_chans=in_chans,
             embed_dim=embed_dim,
+            **embed_args,
         )
         num_patches = self.patch_embed.num_patches
 
@@ -435,7 +442,7 @@ def __init__(
             self.rope = RotaryEmbeddingCat(
                 embed_dim // num_heads,
                 in_pixels=False,
-                feat_shape=self.patch_embed.grid_size,
+                feat_shape=None if dynamic_size else self.patch_embed.grid_size,
                 ref_feat_shape=ref_feat_shape,
             )
         else:
@@ -519,30 +526,44 @@ def reset_classifier(self, num_classes, global_pool=None):
             self.global_pool = global_pool
         self.head = nn.Linear(self.embed_dim, num_classes) if num_classes > 0 else nn.Identity()
 
-    def forward_features(self, x):
-        x = self.patch_embed(x)
+    def _pos_embed(self, x) -> Tuple[torch.Tensor, Optional[torch.Tensor]]:
+        if self.dynamic_size:
+            B, H, W, C = x.shape
+            if self.pos_embed is not None:
+                pos_embed = resample_abs_pos_embed(
+                    self.pos_embed,
+                    (H, W),
+                    num_prefix_tokens=self.num_prefix_tokens,
+                )
+            else:
+                pos_embed = None
+            x = x.view(B, -1, C)
+            rot_pos_embed = self.rope.get_embed(shape=(H, W)) if self.rope is not None else None
+        else:
+            pos_embed = self.pos_embed
+            rot_pos_embed = self.rope.get_embed() if self.rope is not None else None
 
         if self.cls_token is not None:
             x = torch.cat((self.cls_token.expand(x.shape[0], -1, -1), x), dim=1)
-
-        # apply abs position embedding
-        if self.pos_embed is not None:
-            x = x + self.pos_embed
+        if pos_embed is not None:
+            x = x + pos_embed
         x = self.pos_drop(x)
 
         # obtain shared rotary position embedding and apply patch dropout
-        rot_pos_embed = self.rope.get_embed() if self.rope is not None else None
         if self.patch_drop is not None:
             x, keep_indices = self.patch_drop(x)
             if rot_pos_embed is not None and keep_indices is not None:
                 rot_pos_embed = apply_keep_indices_nlc(x, rot_pos_embed, keep_indices)
+        return x, rot_pos_embed
 
+    def forward_features(self, x):
+        x = self.patch_embed(x)
+        x, rot_pos_embed = self._pos_embed(x)
         for blk in self.blocks:
             if self.grad_checkpointing and not torch.jit.is_scripting():
                 x = checkpoint(blk, x, rope=rot_pos_embed)
             else:
                 x = blk(x, rope=rot_pos_embed)
-
         x = self.norm(x)
         return x