From f4f90c487cbc247952689e906519d8e2eb21da99 Mon Sep 17 00:00:00 2001
From: Volpeon <git@volpeon.ink>
Date: Fri, 6 Jan 2023 09:07:18 +0100
Subject: Add contextmanager to EMAModel to apply weights temporarily

---
 train_ti.py      | 57 ++++++++++++++++++++++++--------------------------------
 training/util.py | 12 ++++++++++++
 2 files changed, 36 insertions(+), 33 deletions(-)

diff --git a/train_ti.py b/train_ti.py
index 2f13128..aa2bf02 100644
--- a/train_ti.py
+++ b/train_ti.py
@@ -5,6 +5,7 @@ import logging
 import copy
 from pathlib import Path
 from functools import partial
+from contextlib import nullcontext
 
 import torch
 import torch.utils.checkpoint
@@ -509,20 +510,15 @@ class Checkpointer(CheckpointerBase):
 
         text_encoder = self.accelerator.unwrap_model(self.text_encoder)
 
-        if self.ema_embeddings is not None:
-            orig_weights = text_encoder.text_model.embeddings.temp_token_embedding
-            ema_weights = copy.deepcopy(text_encoder.text_model.embeddings.temp_token_embedding)
-            self.ema_embeddings.copy_to(ema_weights.parameters())
-            text_encoder.text_model.embeddings.temp_token_embedding = ema_weights
+        ema_context = self.ema_embeddings.apply_temporary(
+            text_encoder.text_model.embeddings.temp_token_embedding.parameters()) if self.ema_embeddings is not None else nullcontext()
 
-        for (token, ids) in zip(self.placeholder_token, self.new_ids):
-            text_encoder.text_model.embeddings.save_embed(
-                ids,
-                checkpoints_path.joinpath(f"{slugify(token)}_{step}_{postfix}.bin")
-            )
-
-        if self.ema_embeddings is not None:
-            text_encoder.text_model.embeddings.temp_token_embedding = orig_weights
+        with ema_context:
+            for (token, ids) in zip(self.placeholder_token, self.new_ids):
+                text_encoder.text_model.embeddings.save_embed(
+                    ids,
+                    checkpoints_path.joinpath(f"{slugify(token)}_{step}_{postfix}.bin")
+                )
 
         del text_encoder
 
@@ -530,30 +526,25 @@ class Checkpointer(CheckpointerBase):
     def save_samples(self, step, num_inference_steps, guidance_scale=7.5, eta=0.0):
         text_encoder = self.accelerator.unwrap_model(self.text_encoder)
 
-        if self.ema_embeddings is not None:
-            orig_weights = text_encoder.text_model.embeddings.temp_token_embedding
-            ema_weights = copy.deepcopy(text_encoder.text_model.embeddings.temp_token_embedding)
-            self.ema_embeddings.copy_to(ema_weights.parameters())
-            text_encoder.text_model.embeddings.temp_token_embedding = ema_weights
-
-        orig_dtype = text_encoder.dtype
-        text_encoder.to(dtype=self.weight_dtype)
+        ema_context = self.ema_embeddings.apply_temporary(
+            text_encoder.text_model.embeddings.temp_token_embedding.parameters()) if self.ema_embeddings is not None else nullcontext()
 
-        pipeline = VlpnStableDiffusion(
-            text_encoder=text_encoder,
-            vae=self.vae,
-            unet=self.unet,
-            tokenizer=self.tokenizer,
-            scheduler=self.scheduler,
-        ).to(self.accelerator.device)
-        pipeline.set_progress_bar_config(dynamic_ncols=True)
+        with ema_context:
+            orig_dtype = text_encoder.dtype
+            text_encoder.to(dtype=self.weight_dtype)
 
-        super().save_samples(pipeline, step, num_inference_steps, guidance_scale, eta)
+            pipeline = VlpnStableDiffusion(
+                text_encoder=text_encoder,
+                vae=self.vae,
+                unet=self.unet,
+                tokenizer=self.tokenizer,
+                scheduler=self.scheduler,
+            ).to(self.accelerator.device)
+            pipeline.set_progress_bar_config(dynamic_ncols=True)
 
-        text_encoder.to(dtype=orig_dtype)
+            super().save_samples(pipeline, step, num_inference_steps, guidance_scale, eta)
 
-        if self.ema_embeddings is not None:
-            text_encoder.text_model.embeddings.temp_token_embedding = orig_weights
+            text_encoder.to(dtype=orig_dtype)
 
         del text_encoder
         del pipeline
diff --git a/training/util.py b/training/util.py
index 93b6248..6f1e85a 100644
--- a/training/util.py
+++ b/training/util.py
@@ -2,6 +2,7 @@ from pathlib import Path
 import json
 import copy
 from typing import Iterable
+from contextlib import contextmanager
 
 import torch
 from PIL import Image
@@ -259,3 +260,14 @@ class EMAModel:
                 raise ValueError("collected_params must all be Tensors")
             if len(self.collected_params) != len(self.shadow_params):
                 raise ValueError("collected_params and shadow_params must have the same length")
+
+    @contextmanager
+    def apply_temporary(self, parameters):
+        try:
+            parameters = list(parameters)
+            original_params = [p.clone() for p in parameters]
+            self.copy_to(parameters)
+            yield
+        finally:
+            for s_param, param in zip(original_params, parameters):
+                param.data.copy_(s_param.data)
-- 
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