From 1e98f4bafce68ab71d46f48f4e1340e58f14300d Mon Sep 17 00:00:00 2001
From: Kevin Turner <83819+keturn@users.noreply.github.com>
Date: Thu, 10 Nov 2022 15:27:25 -0800
Subject: [PATCH] diffusers: let the scheduler do its scaling of the initial
 latents

Remove IPNDM scheduler; it is not behaving.
---
 backend/modules/parameters.py              | 1 -
 ldm/invoke/args.py                         | 1 -
 ldm/invoke/generator/diffusers_pipeline.py | 2 ++
 3 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/backend/modules/parameters.py b/backend/modules/parameters.py
index 130d04d64a..9055297671 100644
--- a/backend/modules/parameters.py
+++ b/backend/modules/parameters.py
@@ -13,7 +13,6 @@ SAMPLER_CHOICES = [
     "k_lms",
     "plms",
     # diffusers:
-    "ipndm",
     "pndm",
 ]
 
diff --git a/ldm/invoke/args.py b/ldm/invoke/args.py
index a58617a511..f1b5e9029d 100644
--- a/ldm/invoke/args.py
+++ b/ldm/invoke/args.py
@@ -109,7 +109,6 @@ SAMPLER_CHOICES = [
     'k_lms',
     'plms',
     # diffusers:
-    "ipndm",
     "pndm",
 ]
 
diff --git a/ldm/invoke/generator/diffusers_pipeline.py b/ldm/invoke/generator/diffusers_pipeline.py
index c9fff12e0c..bad21b0956 100644
--- a/ldm/invoke/generator/diffusers_pipeline.py
+++ b/ldm/invoke/generator/diffusers_pipeline.py
@@ -231,6 +231,8 @@ class StableDiffusionGeneratorPipeline(DiffusionPipeline):
                                  run_id: str = None, **extra_step_kwargs):
         if run_id is None:
             run_id = secrets.token_urlsafe(self.ID_LENGTH)
+        # scale the initial noise by the standard deviation required by the scheduler
+        latents *= self.scheduler.init_noise_sigma
         yield PipelineIntermediateState(run_id=run_id, step=-1, timestep=self.scheduler.num_train_timesteps,
                                         latents=latents)
         # NOTE: Depends on scheduler being already initialized!