[Model][Bugfix] Fix batching with multi-image in PixtralHF (#9518)

vllm/model_executor/models/llava.py

@@ -287,6 +287,34 @@ class LlavaForConditionalGeneration(nn.Module, SupportsMultiModal, SupportsPP):
 
         return data
 
+    def _validate_image_sizes(self, images: List[torch.Tensor],
+                              sizes: List[torch.Tensor]) -> List[torch.Tensor]:
+        if not isinstance(sizes, list):
+            sizes = [sizes]
+
+        total_images = sum(size.numel() // 2 for size in sizes)
+        if total_images != len(images):
+            raise ValueError("Mismatch in number of images. "
+                             f"Expected {total_images}, got {len(images)}")
+        img_idx = 0
+        for size in sizes:
+            # Flatten the size tensor to a list of (height, width) pairs
+            size = size.view(-1, 2).tolist()
+            for expected_h, expected_w in size:
+                if img_idx >= len(images):
+                    raise ValueError("Ran out of images before sizes. "
+                                     f"{img_idx} >= {len(images)}")
+                img = images[img_idx]
+                if img.shape[-2:] != (expected_h, expected_w):
+                    raise ValueError(
+                        "Image size mismatch. Expected "
+                        f"{(expected_h, expected_w)}, got {img.shape[-2:]}")
+                if img.shape[-3] != 3:
+                    raise ValueError("Image channel mismatch. Expected 3, "
+                                     f"got {img.shape[-3]}")
+                img_idx += 1
+        return images
+
     def _parse_and_validate_image_input(
             self, **kwargs: object) -> Optional[LlavaImageInputs]:
         pixel_values = kwargs.pop("pixel_values", None)
@@ -305,20 +333,28 @@ class LlavaForConditionalGeneration(nn.Module, SupportsMultiModal, SupportsPP):
             # so we need to produce a list of tensors
             if image_sizes is not None:
                 images = pixel_values
-                if isinstance(images, torch.Tensor):
-                    # if passed as batch take all images
-                    NN, N, B, C, W, H = images.shape
-                    images = images.reshape(NN * N * B, C, W, H)
-                    images = [images[i] for i in range(images.size(0))]
-                elif isinstance(images, list):
-                    # if passed as list flatten lists of tensors
-                    while isinstance(images, list) and len(images) == 1:
-                        images = images[0]
-
-                # TODO: Add validation based on image_sizes
+
+                def flatten_to_3d_tensors(item):
+                    if isinstance(item, torch.Tensor):
+                        if item.dim() >= 3:
+                            return [t for t in item.view(-1, *item.shape[-3:])]
+                        else:
+                            raise ValueError(
+                                f"Unexpected tensor dimension: {item.dim()}")
+                    elif isinstance(item, list):
+                        return [
+                            t for subitem in item
+                            for t in flatten_to_3d_tensors(subitem)
+                        ]
+                    else:
+                        raise ValueError(f"Unexpected type: {type(item)}")
+
+                # Restructure the batched images into a list of lists of images
+                images = flatten_to_3d_tensors(pixel_values)
+
                 return LlavaImagePixelInputs(
                     type="pixel_values",
-                    data=images,
+                    data=self._validate_image_sizes(images, image_sizes),
                 )
 
             return LlavaImagePixelInputs(

vllm/model_executor/models/pixtral.py

@@ -907,17 +907,18 @@ class PixtralHFVisionModel(nn.Module):
     ) -> torch.Tensor:
         """
         Args:
-            pixel_values: tensor of token features for
-                all tokens of all images of shape (N_toks, D)
+            pixel_values: Each image to be processed will be a separate tensor
+                in pixel_values. This means it will be a list of tensors
+                because multiple requests batched can have multiple images,
+                each with their own shape potentially
+
         Returns:
             image_features: tensor of token features for
                 all tokens of all images of shape (N_toks, D)
         """
         # pass images through initial convolution independently
         patch_embeds_list = [
-            self.patch_conv(
-                img.reshape(-1, img.shape[-3], img.shape[-2],
-                            img.shape[-1]).to(self.dtype))
+            self.patch_conv(img.unsqueeze(0).to(self.dtype))
             for img in pixel_values
         ]