From c96073646bbb638d7d78fdd7d9fdeed08d1454b5 Mon Sep 17 00:00:00 2001
From: Volpeon <git@volpeon.ink>
Date: Sat, 1 Apr 2023 16:30:36 +0200
Subject: Experimental: TI via LoRA

---
 models/clip/embeddings.py | 53 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 38 insertions(+), 15 deletions(-)

(limited to 'models/clip/embeddings.py')

diff --git a/models/clip/embeddings.py b/models/clip/embeddings.py
index 9abd1bb..88e0cc0 100644
--- a/models/clip/embeddings.py
+++ b/models/clip/embeddings.py
@@ -31,25 +31,47 @@ def resize_embedding(old_embedding: nn.Embedding, new_num_embeddings: int, initi
     return new_embedding
 
 
+class OverlayLinear(nn.Module):
+    def __init__(self, in_features, out_features, rank=4):
+        super().__init__()
+
+        if rank > min(in_features, out_features):
+            raise ValueError(f"Rank {rank} must be less or equal than {min(in_features, out_features)}")
+
+        self.rank = rank
+        self.down = nn.Linear(in_features, rank, bias=False)
+        self.up = nn.Linear(rank, out_features, bias=False)
+        self.reset()
+
+    def reset(self):
+        nn.init.normal_(self.down.weight, std=1 / self.rank)
+        nn.init.zeros_(self.up.weight)
+
+    def forward(self, hidden_states):
+        orig_dtype = hidden_states.dtype
+        dtype = self.down.weight.dtype
+
+        down_hidden_states = self.down(hidden_states.to(dtype))
+        up_hidden_states = self.up(down_hidden_states)
+
+        return up_hidden_states.to(orig_dtype)
+
+
 class ManagedCLIPTextEmbeddings(CLIPTextEmbeddings):
-    def __init__(self, config: CLIPTextConfig, embeddings: CLIPTextEmbeddings):
+    def __init__(self, config: CLIPTextConfig, embeddings: CLIPTextEmbeddings, rank: int = 128):
         super().__init__(config)
 
         self.token_embedding = embeddings.token_embedding
         self.position_embedding = embeddings.position_embedding
         self.initializer_factor = config.initializer_factor
 
-        self.temp_token_embedding = nn.Embedding(
-            self.token_embedding.num_embeddings,
-            self.token_embedding.embedding_dim,
-            device=self.token_embedding.weight.device,
-            dtype=self.token_embedding.weight.dtype
-        )
-        self.temp_token_embedding.weight.data = self.token_embedding.weight.data.clone().detach()
+        self.overlay = OverlayLinear(self.token_embedding.embedding_dim, self.token_embedding.embedding_dim, rank)
         self.temp_token_ids = torch.tensor([], dtype=torch.long)
 
+    def reset_overlay(self):
+        self.overlay.reset()
+
     def resize(self, size: int):
-        self.temp_token_embedding = resize_embedding(self.temp_token_embedding, size, self.initializer_factor)
         self.token_embedding = resize_embedding(self.token_embedding, size, self.initializer_factor)
 
     def add_embed(
@@ -74,8 +96,8 @@ class ManagedCLIPTextEmbeddings(CLIPTextEmbeddings):
                 initializer = self.get_embed(initializer)
 
         initializer = initializer.to(
-            device=self.temp_token_embedding.weight.device,
-            dtype=self.temp_token_embedding.weight.dtype,
+            device=self.token_embedding.weight.device,
+            dtype=self.token_embedding.weight.dtype,
         )
 
         if initializer_noise != 0:
@@ -84,7 +106,6 @@ class ManagedCLIPTextEmbeddings(CLIPTextEmbeddings):
         token_ids = torch.tensor(token_ids, dtype=torch.long)
 
         self.temp_token_ids = torch.cat([self.temp_token_ids, token_ids])
-        self.temp_token_embedding.weight.data[token_ids] = initializer
         self.token_embedding.weight.data[token_ids] = initializer
 
     def load_embed(self, input_ids: list[int], filename: Path):
@@ -95,7 +116,10 @@ class ManagedCLIPTextEmbeddings(CLIPTextEmbeddings):
         save_file({"embed": self.get_embed(input_ids)}, filename)
 
     def persist(self):
-        self.token_embedding.weight.data[self.temp_token_ids] = self.temp_token_embedding.weight.data[self.temp_token_ids]
+        self.token_embedding.weight.data[self.temp_token_ids] += self.overlay(
+            self.token_embedding.weight.data[self.temp_token_ids]
+        )
+        self.overlay.reset()
         self.temp_token_ids = torch.tensor([], dtype=torch.long)
 
     def get_embed(self, input_ids: Union[list[int], torch.LongTensor]):
@@ -103,9 +127,8 @@ class ManagedCLIPTextEmbeddings(CLIPTextEmbeddings):
             input_ids = torch.tensor(input_ids, device=self.token_embedding.weight.device, dtype=torch.long)
 
         embeds = self.token_embedding(input_ids)
-
         mask = torch.isin(input_ids, self.temp_token_ids.to(input_ids.device))
-        embeds[mask] = self.temp_token_embedding(input_ids)[mask]
+        embeds[mask] += self.overlay(embeds[mask])
 
         return embeds
 
-- 
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