From 775b254d49cfe29d46f3f37aba730e3885611d91 Mon Sep 17 00:00:00 2001
From: Wagner Bruna <wbruna@yahoo.com>
Date: Mon, 15 Dec 2025 12:18:14 -0300
Subject: [PATCH] fix: consistently pass 2nd-order samplers half steps as
 negatives

Makes dpm2 and dpm++2s_a match the heun implementation.
---
 denoiser.hpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/denoiser.hpp b/denoiser.hpp
index 32f402786..c43504059 100644
--- a/denoiser.hpp
+++ b/denoiser.hpp
@@ -830,7 +830,7 @@ static bool sample_k_diffusion(sample_method_t method,
 
             for (int i = 0; i < steps; i++) {
                 // denoise
-                ggml_tensor* denoised = model(x, sigmas[i], i + 1);
+                ggml_tensor* denoised = model(x, sigmas[i], -(i + 1));
                 if (denoised == nullptr) {
                     return false;
                 }
@@ -888,7 +888,7 @@ static bool sample_k_diffusion(sample_method_t method,
 
             for (int i = 0; i < steps; i++) {
                 // denoise
-                ggml_tensor* denoised = model(x, sigmas[i], i + 1);
+                ggml_tensor* denoised = model(x, sigmas[i], -(i + 1));
                 if (denoised == nullptr) {
                     return false;
                 }