From: Kevin Boyd <kevin.boyd@uconn.edu>
Date: Wed, 10 Jul 2019 22:01:59 +0000 (-0400)
Subject: Use const views in matrix determinant calculation
X-Git-Url: http://biod.pnpi.spb.ru/gitweb/?a=commitdiff_plain;h=0b95cdce242097859db073a3df3bcff73aacfe25;p=alexxy%2Fgromacs.git

Use const views in matrix determinant calculation

Reduces scope of the matrix.h implementation to just reals

Change-Id: Ide66967b35ffc58b3e61c403d3ce1862b5f5b8ca
---

diff --git a/src/gromacs/math/matrix.h b/src/gromacs/math/matrix.h
index ed225ad585..665fbe77ab 100644
--- a/src/gromacs/math/matrix.h
+++ b/src/gromacs/math/matrix.h
@@ -68,8 +68,7 @@ using Matrix3x3Span      = Matrix3x3::view_type;
 using Matrix3x3ConstSpan = Matrix3x3::const_view_type;
 
 //! Determinant of a 3x3 matrix
-template <class ElementType>
-ElementType determinant(const BasicMatrix3x3<ElementType> matrix)
+constexpr real determinant(Matrix3x3ConstSpan matrix)
 {
     return (  matrix(0, 0)*(matrix(1, 1)*matrix(2, 2)-matrix(2, 1)*matrix(1, 2))
               -matrix(1, 0)*(matrix(0, 1)*matrix(2, 2)-matrix(2, 1)*matrix(0, 2))
diff --git a/src/gromacs/math/tests/matrix.cpp b/src/gromacs/math/tests/matrix.cpp
index 406022aa1d..0d75840872 100644
--- a/src/gromacs/math/tests/matrix.cpp
+++ b/src/gromacs/math/tests/matrix.cpp
@@ -142,29 +142,23 @@ TEST_F(MatrixTest, staticMultiDimArrayExtent)
     EXPECT_EQ(matrix_.extent(1), 3);
 }
 
-TEST_F(MatrixTest, determinantWorksForInt)
+TEST_F(MatrixTest, determinantWorks)
 {
-    const BasicMatrix3x3<int> mat = {{6, 4, 2, 1, -2, 8, 1, 5, 7}};
-    EXPECT_EQ(determinant(mat), -306);
-}
-
-TEST_F(MatrixTest, determinantWorksForFloat)
-{
-    const BasicMatrix3x3<float> mat = {{1.0, 2.0, 3.0,
-                                        0.0, 1.0, 4.0,
-                                        5.0, 6.0, 0.0}};
+    const Matrix3x3 mat = {{1.0, 2.0, 3.0,
+                            0.0, 1.0, 4.0,
+                            5.0, 6.0, 0.0}};
     EXPECT_EQ(determinant(mat), 1);
 }
 
 TEST_F(MatrixTest, noninvertableDeterminantIsZero)
 {
-    const BasicMatrix3x3<int> mat = {{1, 0, 0, 0, 1, 0, 0, 0, 0}};
+    const Matrix3x3 mat = {{1, 0, 0, 0, 1, 0, 0, 0, 0}};
     EXPECT_EQ(determinant(mat), 0);
 }
 
 TEST_F(MatrixTest, determinantOfDiagonalMatrix)
 {
-    const BasicMatrix3x3<int> mat = {{2, 0, 0, 0, 3, 0, 0, 0, 4}};
+    const Matrix3x3 mat = {{2, 0, 0, 0, 3, 0, 0, 0, 4}};
     EXPECT_EQ(determinant(mat), 24);
 }