From 875414ea63bc572358e07699058e9dc18343773a Mon Sep 17 00:00:00 2001
From: Matthew Douglas <38992547+matthewdouglas@users.noreply.github.com>
Date: Mon, 4 Nov 2024 12:33:32 -0500
Subject: [PATCH] add comment

---
 bitsandbytes/autograd/_functions.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/bitsandbytes/autograd/_functions.py b/bitsandbytes/autograd/_functions.py
index d40b3f706..7b1cccb23 100644
--- a/bitsandbytes/autograd/_functions.py
+++ b/bitsandbytes/autograd/_functions.py
@@ -353,9 +353,13 @@ def forward(
 
             # Extract the corresponding weights
             if state.has_fp16_weights:
-                state.subB = B[:, state.idx].t()  # .contiguous()
+                state.subB = B[:, state.idx].t()
             else:
-                outliers = state.CB[:, state.idx]  # .clone()
+                outliers = state.CB[:, state.idx]
+
+                # To dequantize our weights associated with the input outliers,
+                # we want to divide by 127. It's however more performant to multiply
+                # by the reciprocal.
                 state.subB = (7.874016e-3 * outliers * state.SCB.view(-1, 1)).t().to(A.dtype)
         else:
             subA = None