⚡️ Speed up function validate_and_format_image_pairs by 28%

src/transformers/models/lightglue/image_processing_lightglue.py

@@ -123,20 +123,36 @@ def validate_and_format_image_pairs(images: ImageInput):
 
     def _is_valid_image(image):
         """images is a PIL Image or a 3D array."""
-        return is_pil_image(image) or (
-            is_valid_image(image) and get_image_type(image) != ImageType.PIL and len(image.shape) == 3
-        )
+        if is_pil_image(image):
+            return True
+        if not is_valid_image(image):
+            return False
+        return get_image_type(image) != ImageType.PIL and len(image.shape) == 3
 
     if isinstance(images, list):
-        if len(images) == 2 and all((_is_valid_image(image)) for image in images):
-            return images
-        if all(
-            isinstance(image_pair, list)
-            and len(image_pair) == 2
-            and all(_is_valid_image(image) for image in image_pair)
-            for image_pair in images
-        ):
-            return [image for image_pair in images for image in image_pair]
+        n_images = len(images)
+        if n_images == 2:
+            # Evaluate _is_valid_image for both images only once, no generator/all overhead.
+            a, b = images[0], images[1]
+            if _is_valid_image(a) and _is_valid_image(b):
+                return images
+        # Determine if this is a list of pairs (and if all pairs are valid)
+        # Avoid nested all/generators for performance.
+        is_pairs = True
+        for image_pair in images:
+            if not (isinstance(image_pair, list) and len(image_pair) == 2):
+                is_pairs = False
+                break
+            a, b = image_pair[0], image_pair[1]
+            if not (_is_valid_image(a) and _is_valid_image(b)):
+                is_pairs = False
+                break
+        if is_pairs:
+            # Use in-place extension to a flat list for better performance and lower memory than list comprehension
+            result = []
+            for image_pair in images:
+                result.extend(image_pair)
+            return result
     raise ValueError(error_message)