ENH: scalarMatrices: Add determinant calculation

src/OpenFOAM/matrices/SquareMatrix/SquareMatrix.C

@@ -0,0 +1,73 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2013 OpenFOAM Foundation
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "SquareMatrix.H"
+#include "labelList.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+template<class Type>
+Foam::scalar Foam::detDecomposed
+(
+    const SquareMatrix<Type>& matrix,
+    const label sign
+)
+{
+    scalar diagProduct = 1.0;
+
+    for (label i = 0; i < matrix.n(); ++i)
+    {
+        diagProduct *= matrix[i][i];
+    }
+
+    return sign*diagProduct;
+}
+
+
+template<class Type>
+Foam::scalar Foam::det(const SquareMatrix<Type>& matrix)
+{
+    SquareMatrix<Type> matrixTmp = matrix;
+
+    labelList pivotIndices(matrix.n());
+    label sign;
+    LUDecompose(matrixTmp, pivotIndices, sign);
+
+    return detDecomposed(matrixTmp, sign);
+}
+
+
+template<class Type>
+Foam::scalar Foam::det(SquareMatrix<Type>& matrix)
+{
+    labelList pivotIndices(matrix.n());
+    label sign;
+    LUDecompose(matrix, pivotIndices, sign);
+
+    return detDecomposed(matrix, sign);
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //