From 0eb2f339e865c3c4a75297ae8f355e490a28bc6d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Villemot?= <sebastien@dynare.org>
Date: Wed, 10 Mar 2021 14:44:19 +0100
Subject: [PATCH] =?UTF-8?q?Manual:=20add=20a=20short=20description=20of=20?=
 =?UTF-8?q?how=20decision=20rules=20are=20stored=20at=20order=20=E2=89=A5?=
 =?UTF-8?q?=204?=
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Closes: #1764
(cherry picked from commit a2c5df956ffcc968b9a22cf97311663c861fa6af)
---
 doc/manual/source/the-model-file.rst | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/doc/manual/source/the-model-file.rst b/doc/manual/source/the-model-file.rst
index 155cb0fbe7..aeb2a50ac6 100644
--- a/doc/manual/source/the-model-file.rst
+++ b/doc/manual/source/the-model-file.rst
@@ -3970,6 +3970,20 @@ The coefficients of the decision rules are stored as follows:
   unfolded :math:`G_3` matrix, they must be multiplied by 3 when
   computing the decision rules.
 
+Higher-order approximation
+--------------------------
+
+Higher-order approximations are simply a generalization of what is done at
+order 3.
+
+The steady state is stored in ``oo_.dr.ys`` and the constant correction is
+stored in ``oo_.dr.g_0``. The coefficient for orders 1, 2, 3, 4… are
+respectively stored in ``oo_.dr.g_0``, ``oo_.dr.g_1``, ``oo_.dr.g_2``,
+``oo_.dr.g_3``, ``oo_.dr.g_4``… The columns of those matrices correspond to
+multidimensional indices of state variables, in such a way that symmetric
+elements are never repeated (for more details, see the description of
+``oo_.dr.g_3`` in the third-order case).
+
 
 .. _estim:
 
-- 
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