diff --git a/notes.tex b/notes.tex
index b8d4b7a..967d961 100644
--- a/notes.tex
+++ b/notes.tex
@@ -13,6 +13,7 @@
 \usepackage{todonotes}
 \usepackage{siunitx}
 
+\usepackage{hyperref}
 \usepackage{cleveref}
 
 \title{Notes on initial gradient descent testing}
@@ -27,6 +28,7 @@
 
 Before beginning an implementation of the ``dimensional reduction'' solution method of the charge qubit locating problem, I started with a naïve gradient descent algorithm.
 This gives us something to benchmark against later.
+The (unoptimised and messily written) relevant gradient descent code is available at \url{https://gitea.deepak.science/deepak/pathfinder/src/branch/master/pathfinder/gradient_descent.py}.
 
 \section{gradient descent}