From 02d023c7cdfdfb72ccdbccbac0883b4a1f6ec6d5 Mon Sep 17 00:00:00 2001
From: Tyler Veness <calcmogul@gmail.com>
Date: Wed, 18 May 2022 11:13:21 -0700
Subject: [PATCH 1/2] Replace <Eigen/Dense> with <Eigen/Core>

---
 common/is_approx_equal_abstol.h                       | 2 +-
 common/test_utilities/eigen_matrix_compare.h          | 2 +-
 math/discrete_algebraic_riccati_equation.cc           | 3 +++
 math/discrete_algebraic_riccati_equation.h            | 2 +-
 math/test/discrete_algebraic_riccati_equation_test.cc | 1 +
 5 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/common/is_approx_equal_abstol.h b/common/is_approx_equal_abstol.h
index 9af0c45..b3f369c 100644
--- a/common/is_approx_equal_abstol.h
+++ b/common/is_approx_equal_abstol.h
@@ -2,7 +2,7 @@
 
 #include <vector>
 
-#include <Eigen/Dense>
+#include <Eigen/Core>
 
 namespace drake {
 
diff --git a/common/test_utilities/eigen_matrix_compare.h b/common/test_utilities/eigen_matrix_compare.h
index a595da9..c22567d 100644
--- a/common/test_utilities/eigen_matrix_compare.h
+++ b/common/test_utilities/eigen_matrix_compare.h
@@ -4,7 +4,7 @@
 #include <cmath>
 #include <limits>
 
-#include <Eigen/Dense>
+#include <Eigen/Core>
 #include <gtest/gtest.h>
 
 #include "drake/common/text_logging.h"
diff --git a/math/discrete_algebraic_riccati_equation.cc b/math/discrete_algebraic_riccati_equation.cc
index 901f2ef..20ea2b7 100644
--- a/math/discrete_algebraic_riccati_equation.cc
+++ b/math/discrete_algebraic_riccati_equation.cc
@@ -1,5 +1,8 @@
 #include "drake/math/discrete_algebraic_riccati_equation.h"
 
+#include <Eigen/Eigenvalues>
+#include <Eigen/QR>
+
 #include "drake/common/drake_assert.h"
 #include "drake/common/drake_throw.h"
 #include "drake/common/is_approx_equal_abstol.h"
diff --git a/math/discrete_algebraic_riccati_equation.h b/math/discrete_algebraic_riccati_equation.h
index 891373f..df7a58b 100644
--- a/math/discrete_algebraic_riccati_equation.h
+++ b/math/discrete_algebraic_riccati_equation.h
@@ -3,7 +3,7 @@
 #include <cmath>
 #include <cstdlib>
 
-#include <Eigen/Dense>
+#include <Eigen/Core>
 
 namespace drake {
 namespace math {
diff --git a/math/test/discrete_algebraic_riccati_equation_test.cc b/math/test/discrete_algebraic_riccati_equation_test.cc
index 533ced1..e4ecfd2 100644
--- a/math/test/discrete_algebraic_riccati_equation_test.cc
+++ b/math/test/discrete_algebraic_riccati_equation_test.cc
@@ -1,5 +1,6 @@
 #include "drake/math/discrete_algebraic_riccati_equation.h"
 
+#include <Eigen/Eigenvalues>
 #include <gtest/gtest.h>
 
 #include "drake/common/test_utilities/eigen_matrix_compare.h"