(doc/fluxion/ld) add SDXLUNet docstrings

src/refiners/foundationals/latent_diffusion/stable_diffusion_xl/unet.py

@@ -239,7 +239,24 @@ class OutputBlock(fl.Chain):
 
 
 class SDXLUNet(fl.Chain):
-    def __init__(self, in_channels: int, device: Device | str | None = None, dtype: DType | None = None) -> None:
+    """Stable Diffusion XL U-Net.
+
+    See [[arXiv:2307.01952] SDXL: Improving Latent Diffusion Models for High-Resolution Image Synthesis](https://arxiv.org/abs/2307.01952) for more details.
+    """
+
+    def __init__(
+        self,
+        in_channels: int,
+        device: Device | str | None = None,
+        dtype: DType | None = None,
+    ) -> None:
+        """Initialize the U-Net.
+
+        Args:
+            in_channels: Number of input channels.
+            device: Device to use for computation.
+            dtype: Data type to use for computation.
+        """
         self.in_channels = in_channels
         super().__init__(
             TimestepEncoder(device=device, dtype=dtype),
@@ -273,13 +290,45 @@ class SDXLUNet(fl.Chain):
         }
 
     def set_clip_text_embedding(self, clip_text_embedding: Tensor) -> None:
+        """Set the clip text embedding context.
+
+        Note:
+            This context is required by the `SDXLCrossAttention` blocks.
+
+        Args:
+            clip_text_embedding: The CLIP text embedding tensor.
+        """
         self.set_context(context="cross_attention_block", value={"clip_text_embedding": clip_text_embedding})
 
     def set_timestep(self, timestep: Tensor) -> None:
+        """Set the timestep context.
+
+        Note:
+            This is required by `TimestepEncoder`.
+
+        Args:
+            timestep: The timestep tensor.
+        """
         self.set_context(context="diffusion", value={"timestep": timestep})
 
     def set_time_ids(self, time_ids: Tensor) -> None:
+        """Set the time IDs context.
+
+        Note:
+            This is required by `TextTimeEmbedding`.
+
+        Args:
+            time_ids: The time IDs tensor.
+        """
         self.set_context(context="diffusion", value={"time_ids": time_ids})
 
     def set_pooled_text_embedding(self, pooled_text_embedding: Tensor) -> None:
+        """Set the pooled text embedding context.
+
+        Note:
+            This is required by `TextTimeEmbedding`.
+
+        Args:
+            pooled_text_embedding: The pooled text embedding tensor.
+        """
         self.set_context(context="diffusion", value={"pooled_text_embedding": pooled_text_embedding})