From 863e5e23176b70abd210e6b3fbdf742073c7b103 Mon Sep 17 00:00:00 2001
From: Thomas Fischer <thomas.fischer@ufz.de>
Date: Fri, 19 Sep 2014 12:00:21 +0200
Subject: [PATCH] [MeshGeoToolsLib] Heuristic search length.
Computes the search length using a heuristic.
---
MeshGeoToolsLib/HeuristicSearchLength.cpp | 69 +++++++++++++++++++++++
MeshGeoToolsLib/HeuristicSearchLength.h | 36 ++++++++++++
2 files changed, 105 insertions(+)
create mode 100644 MeshGeoToolsLib/HeuristicSearchLength.cpp
create mode 100644 MeshGeoToolsLib/HeuristicSearchLength.h
diff --git a/MeshGeoToolsLib/HeuristicSearchLength.cpp b/MeshGeoToolsLib/HeuristicSearchLength.cpp
new file mode 100644
index 00000000000..fad637711b3
--- /dev/null
+++ b/MeshGeoToolsLib/HeuristicSearchLength.cpp
@@ -0,0 +1,69 @@
+/**
+ * @file
+ * @date 2014-09-19
+ * @brief Implementation of heuristic search length strategy.
+ *
+ * @copyright
+ * Copyright (c) 2012-2014, OpenGeoSys Community (http://www.opengeosys.org)
+ * Distributed under a Modified BSD License.
+ * See accompanying file LICENSE.txt or
+ * http://www.opengeosys.org/LICENSE.txt
+ */
+
+#include "HeuristicSearchLength.h"
+
+// ThirdParty/logog
+#include "logog/include/logog.hpp"
+
+#include "MeshLib/Elements/Element.h"
+#include "MeshLib/Elements/Line.h"
+
+namespace MeshGeoToolsLib
+{
+
+HeuristicSearchLength::HeuristicSearchLength(MeshLib::Mesh const& mesh)
+: SearchLength(mesh)
+{
+ double sum (0.0);
+ double sum_of_sqr (0.0);
+ std::size_t edge_cnt(0);
+ std::vector<MeshLib::Element*> const& elements(_mesh.getElements());
+
+ for (std::vector<MeshLib::Element*>::const_iterator it(elements.cbegin());
+ it != elements.cend(); ++it) {
+ std::size_t const n_edges((*it)->getNEdges());
+ for (std::size_t k(0); k<n_edges; k++) {
+ MeshLib::Line const* edge(static_cast<MeshLib::Line const*>((*it)->getEdge(k)));
+ if (!edge) {
+ delete edge;
+ continue;
+ }
+ double const len(edge->getLength());
+ sum += len;
+ sum_of_sqr += len*len;
+ delete edge;
+ }
+ edge_cnt += n_edges;
+ }
+
+ const double mu (sum/edge_cnt);
+ const double s (sqrt(1.0/(edge_cnt-1) * (sum_of_sqr - (sum*sum)/edge_cnt) ));
+ // heuristic to prevent negative search lengths
+ // in the case of a big standard deviation s
+ double c(2.0);
+ while (mu < c * s) {
+ c *= 0.9;
+ }
+
+ _search_length = (mu - c * s)/2;
+
+ DBUG("[MeshNodeSearcher::MeshNodeSearcher] Calculated search length for mesh \"%s\" is %f.",
+ _mesh.getName().c_str(), _search_length);
+}
+
+double HeuristicSearchLength::getSearchLength() const
+{
+ return _search_length;
+}
+
+} // end namespace MeshGeoToolsLib
diff --git a/MeshGeoToolsLib/HeuristicSearchLength.h b/MeshGeoToolsLib/HeuristicSearchLength.h
new file mode 100644
index 00000000000..a39bd49f112
--- /dev/null
+++ b/MeshGeoToolsLib/HeuristicSearchLength.h
@@ -0,0 +1,36 @@
+/**
+ * @file
+ * @date 2014-09-19
+ * @brief Interface for heuristic search length strategy.
+ *
+ * @copyright
+ * Copyright (c) 2012-2014, OpenGeoSys Community (http://www.opengeosys.org)
+ * Distributed under a Modified BSD License.
+ * See accompanying file LICENSE.txt or
+ * http://www.opengeosys.org/LICENSE.txt
+ */
+
+#ifndef HEURISTICSEARCHLENGTH_H_
+#define HEURISTICSEARCHLENGTH_H_
+
+#include "MeshGeoToolsLib/SearchLength.h"
+
+namespace MeshGeoToolsLib
+{
+
+/// HeuristicSearchLength implements a mesh dependent criterion for searching
+/// mesh nodes near a geometry. For this purpose it computes the average
+/// \f$\mu\f$ and the standard deviation \f$\sigma\f$ of edge length of mesh
+/// elements. The search lenght is set to \f$\mu-2\sigma\f$. This strategy
+/// is usefull for meshes with different sizes of elements.
+class HeuristicSearchLength : public SearchLength
+{
+public:
+ HeuristicSearchLength(MeshLib::Mesh const& mesh);
+ virtual double getSearchLength() const;
+};
+
+} // end namespace MeshGeoToolsLib
+
+#endif
+
--
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