From be193258f34e77fbba19b3af7670a1356dc3a8bd Mon Sep 17 00:00:00 2001
From: Taylor Erwin <1065262+terwin@users.noreply.github.com>
Date: Fri, 19 Feb 2021 18:11:52 -0500
Subject: [PATCH 1/2] Re-enable eigendecomp test

This reverts commit 08caf6ff39be6c1cbc0dc48298f1055652d3e455.
---
 unit_test/tstBatchedLinearAlgebra.hpp | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/unit_test/tstBatchedLinearAlgebra.hpp b/unit_test/tstBatchedLinearAlgebra.hpp
index ca1a5c2..4d230bd 100644
--- a/unit_test/tstBatchedLinearAlgebra.hpp
+++ b/unit_test/tstBatchedLinearAlgebra.hpp
@@ -711,7 +711,6 @@ void kernelTest()
 }
 
 //---------------------------------------------------------------------------//
-/*
 void eigendecompositionTest()
 {
     LinearAlgebra::Matrix<double, 4, 4> A = {
@@ -822,7 +821,6 @@ void eigendecompositionTest()
         for ( int j = 0; j < 4; ++j )
             EXPECT_FLOAT_EQ( A( i, j ), l_op_ident( i, j ) );
 }
-*/
 
 //---------------------------------------------------------------------------//
 // RUN TESTS
@@ -867,8 +865,7 @@ TEST( TEST_CATEGORY, kernelTest )
     kernelTest<20>();
 }
 
-// FIXME_KOKKOSKERNELS
-// TEST( TEST_CATEGORY, eigendecomposition_test ) { eigendecompositionTest(); }
+TEST( TEST_CATEGORY, eigendecomposition_test ) { eigendecompositionTest(); }
 
 //---------------------------------------------------------------------------//
 

From 278ac1b5d0c9b831b792b09d273511be69f6d495 Mon Sep 17 00:00:00 2001
From: Taylor Erwin <1065262+terwin@users.noreply.github.com>
Date: Fri, 19 Feb 2021 11:24:29 -0500
Subject: [PATCH 2/2] Add test exposing KokkosKernels eigendecomp bug

---
 unit_test/tstBatchedLinearAlgebra.hpp | 44 +++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/unit_test/tstBatchedLinearAlgebra.hpp b/unit_test/tstBatchedLinearAlgebra.hpp
index 4d230bd..0446957 100644
--- a/unit_test/tstBatchedLinearAlgebra.hpp
+++ b/unit_test/tstBatchedLinearAlgebra.hpp
@@ -16,6 +16,8 @@
 
 #include <gtest/gtest.h>
 
+#include <algorithm>
+#include <array>
 #include <random>
 
 using namespace Picasso;
@@ -822,6 +824,43 @@ void eigendecompositionTest()
             EXPECT_FLOAT_EQ( A( i, j ), l_op_ident( i, j ) );
 }
 
+//---------------------------------------------------------------------------//
+// Test a matrix for which the KokkosKernels eigendecomposition gives the wrong
+// answer.
+//---------------------------------------------------------------------------//
+void eigendecompositionTestBad()
+{
+    LinearAlgebra::Matrix<double, 5, 5> A = { { 0.5, 0.0, 2.5, 0.0, 0.0 },
+                                              { 0.0, 0.5, 0.0, 0.0, 0.0 },
+                                              { 0.0, 0.0, 0.5, 0.0, 0.4 },
+                                              { 0.0, 0.0, 0.0, 0.5, 0.0 },
+                                              { 0.0, 0.0, 1.05, 0.0, 0.5 } };
+
+    LinearAlgebra::Vector<double, 5> e_real;
+    LinearAlgebra::Vector<double, 5> e_imag;
+    LinearAlgebra::Matrix<double, 5, 5> u_left;
+    LinearAlgebra::Matrix<double, 5, 5> u_right;
+
+    LinearAlgebra::eigendecomposition( A, e_real, e_imag, u_left, u_right );
+
+    // All eigenvalues should be real
+    for ( int i = 0; i < 5; ++i )
+        EXPECT_EQ( 0.0, e_imag( i ) ) << "i = " << i;
+
+    // Sort eigenvalues
+    std::array<double, 5> sorted_e_real;
+    for ( int i = 0; i < 5; ++i )
+        sorted_e_real[i] = e_real( i );
+    std::sort( sorted_e_real.begin(), sorted_e_real.end() );
+
+    // Test sorted eigenvalues
+    EXPECT_DOUBLE_EQ( -0.14807406984078597, sorted_e_real[0] );
+    EXPECT_DOUBLE_EQ( 0.5, sorted_e_real[1] );
+    EXPECT_DOUBLE_EQ( 0.5, sorted_e_real[2] );
+    EXPECT_DOUBLE_EQ( 0.5, sorted_e_real[3] );
+    EXPECT_DOUBLE_EQ( 1.148074069840786, sorted_e_real[4] );
+}
+
 //---------------------------------------------------------------------------//
 // RUN TESTS
 //---------------------------------------------------------------------------//
@@ -867,6 +906,11 @@ TEST( TEST_CATEGORY, kernelTest )
 
 TEST( TEST_CATEGORY, eigendecomposition_test ) { eigendecompositionTest(); }
 
+TEST( TEST_CATEGORY, eigendecomposition_test_bad )
+{
+    eigendecompositionTestBad();
+}
+
 //---------------------------------------------------------------------------//
 
 } // end namespace Test