From eff47c46c2eb88ed424e2ec24545632ca8a8fa5c Mon Sep 17 00:00:00 2001
From: patavirt <pauli.t.virtanen@jyu.fi>
Date: Tue, 30 Aug 2022 16:30:51 +0300
Subject: [PATCH] DOC

---
 doc/discretization.md | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/doc/discretization.md b/doc/discretization.md
index 15885c2..10f0dfc 100644
--- a/doc/discretization.md
+++ b/doc/discretization.md
@@ -1,10 +1,11 @@
 # Gauge-invariant discretization
 
 We do the discretization of the Usadel equation as follows. We first
-discretize the action $`S`$, and derive the discrete saddle-point
-equation from the discretized action. This simplifies things somewhat,
-because proper handling of the gauge fields is simpler to do
-in the action formulation.
+discretize the action $`S`$. The discrete saddle-point equation or expressions
+for currents are not derived analytically, but instead obtained from the computer
+implementation of the action via automatic differentiation (AD).
+This simplifies things somewhat, because proper handling of the gauge fields is
+simpler to do in the action formulation.
 
 The action is
 ```math
-- 
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