From 054865be9b2d6219f09c71060060111f477dd3fd Mon Sep 17 00:00:00 2001
From: Rene Milk <rene.milk@uni-muenster.de>
Date: Thu, 26 Aug 2010 21:30:29 +0200
Subject: [PATCH] trace function
---
stuff/matrix.hh | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/stuff/matrix.hh b/stuff/matrix.hh
index 76a677df4..1271cc8ab 100644
--- a/stuff/matrix.hh
+++ b/stuff/matrix.hh
@@ -45,6 +45,28 @@ public:
}
};
+template <class FieldMatrixType>
+class MatrixDiagonal : public FieldVector<typename FieldMatrixType::field_type, FieldMatrixType::rows>
+{
+public:
+ MatrixDiagonal(const FieldMatrixType& matrix)
+ {
+ CompileTimeChecker<FieldMatrixType::rows == FieldMatrixType::cols> matrix_must_be_square;
+ for (size_t i = 0; i < FieldMatrixType::rows; i++)
+ (*this)[i] = matrix[i][i];
+ }
+};
+
+template <class FieldMatrixType>
+typename FieldMatrixType::field_type matrixTrace(const FieldMatrixType& matrix)
+{
+ MatrixDiagonal<FieldMatrixType> diag(matrix);
+ typename FieldMatrixType::field_type trace = typename FieldMatrixType::field_type(0);
+ for (size_t i = 0; i < FieldMatrixType::rows; i++)
+ trace += diag[i];
+ return trace;
+}
+
} // namespace Dune
--
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