1 files changed, 27 insertions, 0 deletions

diff --git a/training/lora.py b/training/lora.py
new file mode 100644
index 0000000..d8dc147
--- /dev/null
+++ b/training/lora.py
@@ -0,0 +1,27 @@
+import torch.nn as nn
+from diffusers import ModelMixin, ConfigMixin, XFormersCrossAttnProcessor, register_to_config
+
+
+class LoraAttention(ModelMixin, ConfigMixin):
+    @register_to_config
+    def __init__(self, in_features, out_features, r=4):
+        super().__init__()
+
+        if r > min(in_features, out_features):
+            raise ValueError(
+                f"LoRA rank {r} must be less or equal than {min(in_features, out_features)}"
+            )
+
+        self.lora_down = nn.Linear(in_features, r, bias=False)
+        self.lora_up = nn.Linear(r, out_features, bias=False)
+        self.scale = 1.0
+
+        self.processor = XFormersCrossAttnProcessor()
+
+        nn.init.normal_(self.lora_down.weight, std=1 / r**2)
+        nn.init.zeros_(self.lora_up.weight)
+
+    def __call__(self, attn, hidden_states, encoder_hidden_states=None, attention_mask=None, number=None):
+        hidden_states = self.processor(attn, hidden_states, encoder_hidden_states, attention_mask, number)
+        hidden_states = hidden_states + self.lora_up(self.lora_down(hidden_states)) * self.scale
+        return hidden_states