Added blank prompt preservation

jaretburkett · jaretburkett · commit ee206cfa18b5 · 2025-10-22T14:55:13.000-06:00
diff --git a/extensions_built_in/sd_trainer/SDTrainer.py b/extensions_built_in/sd_trainer/SDTrainer.py
@@ -95,8 +95,13 @@ def __init__(self, process_id: int, job, config: OrderedDict, **kwargs):
                 raise ValueError("diff_output_preservation requires a network to be set")
             if self.train_config.train_text_encoder:
                 raise ValueError("diff_output_preservation is not supported with train_text_encoder")
-            
-            # always do a prior prediction when doing diff output preservation
+        
+        if self.train_config.blank_prompt_preservation:
+            if self.network_config is None:
+                raise ValueError("blank_prompt_preservation requires a network to be set")
+        
+        if self.train_config.blank_prompt_preservation or self.train_config.diff_output_preservation:
+            # always do a prior prediction when doing output preservation
             self.do_prior_prediction = True
         
         # store the loss target for a batch so we can use it in a loss
@@ -343,6 +348,13 @@ def hook_before_train_loop(self):
                     self.sd.text_encoder_to("cpu")
                 flush()
         
+        if self.train_config.blank_prompt_preservation and self.cached_blank_embeds is None:
+            # make sure we have this if not unloading
+            self.cached_blank_embeds = self.sd.encode_prompt("", **encode_kwargs).to(
+                self.device_torch,
+                dtype=self.sd.torch_dtype
+            ).detach()
+        
         if self.train_config.diffusion_feature_extractor_path is not None:
             vae = self.sd.vae
             # if not (self.model_config.arch in ["flux"]) or self.sd.vae.__class__.__name__ == "AutoencoderPixelMixer":
@@ -1769,6 +1781,14 @@ def get_adapter_multiplier():
                         if self.train_config.diff_output_preservation:
                             prior_embeds_to_use = self.diff_output_preservation_embeds.expand_to_batch(noisy_latents.shape[0])
                         
+                        if self.train_config.blank_prompt_preservation:
+                            blank_embeds = self.cached_blank_embeds.clone().detach().to(
+                                self.device_torch, dtype=dtype
+                            )
+                            prior_embeds_to_use = concat_prompt_embeds(
+                                [blank_embeds] * noisy_latents.shape[0]
+                            )
+                        
                         prior_pred = self.get_prior_prediction(
                             noisy_latents=noisy_latents,
                             conditional_embeds=prior_embeds_to_use,
@@ -1944,7 +1964,8 @@ def get_adapter_multiplier():
                         prior_to_calculate_loss = prior_pred
                         # if we are doing diff_output_preservation and not noing inverted masked prior
                         # then we need to send none here so it will not target the prior
-                        if self.train_config.diff_output_preservation and not do_inverted_masked_prior:
+                        doing_preservation = self.train_config.diff_output_preservation or self.train_config.blank_prompt_preservation
+                        if doing_preservation and not do_inverted_masked_prior:
                             prior_to_calculate_loss = None
                         
                         loss = self.calculate_loss(
@@ -1957,24 +1978,34 @@ def get_adapter_multiplier():
                             prior_pred=prior_to_calculate_loss,
                         )
                     
-                    if self.train_config.diff_output_preservation:
+                    if self.train_config.diff_output_preservation or self.train_config.blank_prompt_preservation:
                         # send the loss backwards otherwise checkpointing will fail
                         self.accelerator.backward(loss)
                         normal_loss = loss.detach() # dont send backward again
                         
-                        dop_embeds = self.diff_output_preservation_embeds.expand_to_batch(noisy_latents.shape[0])
-                        dop_pred = self.predict_noise(
+                        with torch.no_grad():
+                            if self.train_config.diff_output_preservation:
+                                preservation_embeds = self.diff_output_preservation_embeds.expand_to_batch(noisy_latents.shape[0])
+                            elif self.train_config.blank_prompt_preservation:
+                                blank_embeds = self.cached_blank_embeds.clone().detach().to(
+                                    self.device_torch, dtype=dtype
+                                )
+                                preservation_embeds = concat_prompt_embeds(
+                                    [blank_embeds] * noisy_latents.shape[0]
+                                )
+                        preservation_pred = self.predict_noise(
                             noisy_latents=noisy_latents.to(self.device_torch, dtype=dtype),
                             timesteps=timesteps,
-                            conditional_embeds=dop_embeds.to(self.device_torch, dtype=dtype),
+                            conditional_embeds=preservation_embeds.to(self.device_torch, dtype=dtype),
                             unconditional_embeds=unconditional_embeds,
                             batch=batch,
                             **pred_kwargs
                         )
-                        dop_loss = torch.nn.functional.mse_loss(dop_pred, prior_pred) * self.train_config.diff_output_preservation_multiplier
-                        self.accelerator.backward(dop_loss)
-                        
-                        loss = normal_loss + dop_loss
+                        multiplier = self.train_config.diff_output_preservation_multiplier if self.train_config.diff_output_preservation else self.train_config.blank_prompt_preservation_multiplier
+                        preservation_loss = torch.nn.functional.mse_loss(preservation_pred, prior_pred) * multiplier
+                        self.accelerator.backward(preservation_loss)
+
+                        loss = normal_loss + preservation_loss
                         loss = loss.clone().detach()
                         # require grad again so the backward wont fail
                         loss.requires_grad_(True)
diff --git a/toolkit/config_modules.py b/toolkit/config_modules.py
@@ -451,7 +451,11 @@ def __init__(self, **kwargs):
         self.diff_output_preservation_multiplier = kwargs.get('diff_output_preservation_multiplier', 1.0)
         # If the trigger word is in the prompt, we will use this class name to replace it eg. "sks woman" -> "woman"
         self.diff_output_preservation_class = kwargs.get('diff_output_preservation_class', '')
-
+        
+        # blank prompt preservation will preserve the model's knowledge of a blank prompt
+        self.blank_prompt_preservation = kwargs.get('blank_prompt_preservation', False)
+        self.blank_prompt_preservation_multiplier = kwargs.get('blank_prompt_preservation_multiplier', 1.0)
+        
         # legacy
         if match_adapter_assist and self.match_adapter_chance == 0.0:
             self.match_adapter_chance = 1.0
@@ -1318,5 +1322,8 @@ def validate_configs(
     if model_config.arch == 'qwen_image_edit':
         if train_config.unload_text_encoder:
             raise ValueError("Cannot cache unload text encoder with qwen_image_edit model. Control images are encoded with text embeddings. You can cache the text embeddings though")
+    
+    if train_config.diff_output_preservation and train_config.blank_prompt_preservation:
+        raise ValueError("Cannot use both differential output preservation and blank prompt preservation at the same time. Please set one of them to False.")
 
     
diff --git a/ui/src/app/jobs/new/SimpleJob.tsx b/ui/src/app/jobs/new/SimpleJob.tsx
@@ -215,12 +215,12 @@ export default function SimpleJob({
               </FormGroup>
             )}
             {modelArch?.additionalSections?.includes('model.qie.match_target_res') && (
-                <Checkbox
-                  label="Match Target Res"
-                  docKey="model.qie.match_target_res"
-                  checked={jobConfig.config.process[0].model.model_kwargs.match_target_res}
-                  onChange={value => setJobConfig(value, 'config.process[0].model.model_kwargs.match_target_res')}
-                />
+              <Checkbox
+                label="Match Target Res"
+                docKey="model.qie.match_target_res"
+                checked={jobConfig.config.process[0].model.model_kwargs.match_target_res}
+                onChange={value => setJobConfig(value, 'config.process[0].model.model_kwargs.match_target_res')}
+              />
             )}
             {modelArch?.additionalSections?.includes('model.layer_offloading') && (
               <>
@@ -586,16 +586,27 @@ export default function SimpleJob({
                 </FormGroup>
               </div>
               <div>
+                {disableSections.includes('train.diff_output_preservation') ||
+                disableSections.includes('train.blank_prompt_preservation') ? null : (
+                  <FormGroup label="Regularization">
+                    <></>
+                  </FormGroup>
+                )}
                 {disableSections.includes('train.diff_output_preservation') ? null : (
                   <>
-                    <FormGroup label="Regularization">
-                      <Checkbox
-                        label="Differential Output Preservation"
-                        className="pt-1"
-                        checked={jobConfig.config.process[0].train.diff_output_preservation || false}
-                        onChange={value => setJobConfig(value, 'config.process[0].train.diff_output_preservation')}
-                      />
-                    </FormGroup>
+                    <Checkbox
+                      label="Differential Output Preservation"
+                      docKey={'train.diff_output_preservation'}
+                      className="pt-1"
+                      checked={jobConfig.config.process[0].train.diff_output_preservation || false}
+                      onChange={value => {
+                        setJobConfig(value, 'config.process[0].train.diff_output_preservation');
+                        if (value && jobConfig.config.process[0].train.blank_prompt_preservation) {
+                          // only one can be enabled at a time
+                          setJobConfig(false, 'config.process[0].train.blank_prompt_preservation');
+                        }
+                      }}
+                    />
                     {jobConfig.config.process[0].train.diff_output_preservation && (
                       <>
                         <NumberInput
@@ -610,7 +621,7 @@ export default function SimpleJob({
                         />
                         <TextInput
                           label="DOP Preservation Class"
-                          className="pt-2"
+                          className="pt-2 pb-4"
                           value={jobConfig.config.process[0].train.diff_output_preservation_class as string}
                           onChange={value =>
                             setJobConfig(value, 'config.process[0].train.diff_output_preservation_class')
@@ -621,6 +632,39 @@ export default function SimpleJob({
                     )}
                   </>
                 )}
+                {disableSections.includes('train.blank_prompt_preservation') ? null : (
+                  <>
+                    <Checkbox
+                      label="Blank Prompt Preservation"
+                      docKey={'train.blank_prompt_preservation'}
+                      className="pt-1"
+                      checked={jobConfig.config.process[0].train.blank_prompt_preservation || false}
+                      onChange={value => {
+                        setJobConfig(value, 'config.process[0].train.blank_prompt_preservation');
+                        if (value && jobConfig.config.process[0].train.diff_output_preservation) {
+                          // only one can be enabled at a time
+                          setJobConfig(false, 'config.process[0].train.diff_output_preservation');
+                        }
+                      }}
+                    />
+                    {jobConfig.config.process[0].train.blank_prompt_preservation && (
+                      <>
+                        <NumberInput
+                          label="BPP Loss Multiplier"
+                          className="pt-2"
+                          value={
+                            (jobConfig.config.process[0].train.blank_prompt_preservation_multiplier as number) || 1.0
+                          }
+                          onChange={value =>
+                            setJobConfig(value, 'config.process[0].train.blank_prompt_preservation_multiplier')
+                          }
+                          placeholder="eg. 1.0"
+                          min={0}
+                        />
+                      </>
+                    )}
+                  </>
+                )}
               </div>
             </div>
           </Card>
diff --git a/ui/src/app/jobs/new/options.ts b/ui/src/app/jobs/new/options.ts
@@ -9,6 +9,7 @@ type DisableableSections =
   | 'network.conv'
   | 'trigger_word'
   | 'train.diff_output_preservation'
+  | 'train.blank_prompt_preservation'
   | 'train.unload_text_encoder'
   | 'slider';
 
diff --git a/ui/src/docs.tsx b/ui/src/docs.tsx
@@ -228,6 +228,36 @@ const docs: { [key: string]: ConfigDoc } = {
       </>
     ),
   },
+  'train.diff_output_preservation': {
+    title: 'Differential Output Preservation',
+    description: (
+      <>
+        Differential Output Preservation (DOP) is a technique to help preserve class of the trained concept during
+        training. For this, you must have a trigger word set to differentiate your concept from its class. For instance,
+        You may be training a woman named Alice. Your trigger word may be "Alice". The class is "woman", since Alice is
+        a woman. We want to teach the model to remember what it knows about the class "woman" while teaching it what is
+        different about Alice. During training, the trainer will make a prediction with your LoRA bypassed and your
+        trigger word in the prompt replaced with the class word. Making "photo of Alice" become "photo of woman". This
+        prediction is called the prior prediction. Each step, we will do the normal training step, but also do another
+        step with this prior prediction and the class prompt in order to teach our LoRA to preserve the knowledge of the
+        class. This should not only improve the performance of your trained concept, but also allow you to do things
+        like "Alice standing next to a woman" and not make both of the people look like Alice.
+      </>
+    ),
+  },
+  'train.blank_prompt_preservation': {
+    title: 'Blank Prompt Preservation',
+    description: (
+      <>
+        Blank Prompt Preservation (BPP) is a technique to help preserve the current models knowledge when unprompted.
+        This will not only help the model become more flexible, but will also help the quality of your concept during
+        inference, especially when a model uses CFG (Classifier Free Guidance) on inference. At each step during
+        training, a prior prediction is made with a blank prompt and with the LoRA disabled. This prediction is then
+        used as a target on an additional training step with a blank prompt, to preserve the model's knowledge when no
+        prompt is given. This helps the model to not overfit to the prompt and retain its generalization capabilities.
+      </>
+    ),
+  },
 };
 
 export const getDoc = (key: string | null | undefined): ConfigDoc | null => {
diff --git a/ui/src/types.ts b/ui/src/types.ts
@@ -135,6 +135,8 @@ export interface TrainConfig {
   diff_output_preservation: boolean;
   diff_output_preservation_multiplier: number;
   diff_output_preservation_class: string;
+  blank_prompt_preservation?: boolean;
+  blank_prompt_preservation_multiplier?: number;
   switch_boundary_every: number;
   loss_type: 'mse' | 'mae' | 'wavelet' | 'stepped';
 }
diff --git a/version.py b/version.py
@@ -1 +1 @@
-VERSION = "0.7.1"
+VERSION = "0.7.2"

Original file line number	Diff line number	Diff line change
`@@ -135,6 +135,8 @@ export interface TrainConfig {`
`135`	`135`	`diff_output_preservation: boolean;`
`136`	`136`	`diff_output_preservation_multiplier: number;`
`137`	`137`	`diff_output_preservation_class: string;`
	`138`	`+ blank_prompt_preservation?: boolean;`
	`139`	`+ blank_prompt_preservation_multiplier?: number;`
`138`	`140`	`switch_boundary_every: number;`
`139`	`141`	`loss_type: 'mse' \| 'mae' \| 'wavelet' \| 'stepped';`
`140`	`142`	`}`