Some fixes in edge collapse algorithm, some more fixes will follow

Examples/GridTools/fix_tiny_collapse.cpp

+#include "inmost.h"
+
+using namespace INMOST;
+
+
+
+int main(int argc, char ** argv)
+{
+	if (argc < 2)
+	{
+		std::cout << "Usage: " << argv[0] << " mesh [mesh_out=grid.vtk]" << std::endl;
+		return -1;
+	}
+
+	std::string grid_out = "grid.vtk";
+	
+	if (argc > 2) grid_out = std::string(argv[2]);
+
+
+	Mesh m;
+	m.Load(argv[1]);
+	
+	Mesh::GeomParam table;
+	table[MEASURE] = CELL;
+	m.PrepareGeometricData(table);
+	
+
+	std::cout << "Start:" << std::endl;
+	std::cout << "Cells: " << m.NumberOfCells() << std::endl;
+	std::cout << "Faces: " << m.NumberOfFaces() << std::endl;
+	std::cout << "Edges: " << m.NumberOfEdges() << std::endl;
+	double tt = Timer();
+	
+	MarkerType collapse = m.CreateMarker();
+	
+	int ncells = 0;
+	
+#pragma omp parallel for reduction(+:ncells)
+	for(int k = 0; k < m.CellLastLocalID(); ++k) if( m.isValidCell(k) )
+	{
+		Cell c = m.CellByLocalID(k);
+		ElementArray<Cell> around = c.BridgeAdjacencies2Cell(FACE);
+		double vol0 = c.Volume(), vol = vol0;
+		for(unsigned l = 0; l < around.size(); ++l)
+			vol += around[l].Volume();
+		if( vol0 / vol < 0.03 )
+		{
+			c.SetMarker(collapse);
+			ncells++;
+		}
+	}
+	std::cout << "collapse cells: " << ncells << std::endl;
+	
+	int nedges = 0;
+	
+#pragma omp parallel for reduction(+:nedges)	
+	for(int k = 0; k < m.EdgeLastLocalID(); ++k) if( m.isValidEdge(k) )
+	{
+		Edge e = m.EdgeByLocalID(k);
+		ElementArray<Cell> around = e.getCells();
+		for(unsigned l = 0; l < around.size(); ++l)
+			if( around[l].GetMarker(collapse) )
+			{
+				e.SetMarker(collapse);
+				nedges++;
+				break;
+			}
+	}
+	
+	std::cout << "collapse edges: " << nedges << std::endl;
+	
+	int ncollapsed = 0;
+	for(int k = 0; k < m.EdgeLastLocalID(); ++k) if( m.isValidEdge(k) )
+	{
+		Edge e = m.EdgeByLocalID(k);
+		if( e.GetMarker(collapse) ) 
+		{
+			Edge::CollapseEdge(e,0);
+			ncollapsed++;
+			if( ncollapsed % 100 == 0 )
+				m.Save("collapsed.vtk");
+			if( !Element::CheckConnectivity(&m) )
+			{
+				std::cout << "connectivity is bad" << std::endl;
+				throw -1;
+			}
+		}
+	}
+	
+	
+	
+	std::cout << "Time to fix tiny:" << Timer() - tt << std::endl;
+	std::cout << "Cells: " << m.NumberOfCells() << std::endl;
+	std::cout << "Faces: " << m.NumberOfFaces() << std::endl;
+	std::cout << "Edges: " << m.NumberOfEdges() << std::endl;
+
+	m.Save(grid_out);
+	return 0;
+}