/// <summary>
/// Creates the sub-grids of the clustering
/// </summary>
/// <param name="numOfClusters">Number of clusters</param>
/// <returns>A list of sub-grids</returns>
public Clustering CreateClustering(int numOfClusters, SubGrid subGrid = null)
{
if (subGrid == null)
{
subGrid = new SubGrid(CellMask.GetFullMask(gridData));
}
// Attention: numOfCells can equal all local cells or only the local cells of a subgrid,
// e.g., the fluid cells in an IBM simulation
int numOfCells = subGrid.LocalNoOfCells;
MultidimensionalArray cellMetric = GetStableTimestepSize(subGrid);
MultidimensionalArray means = CreateInitialMeans(cellMetric, numOfClusters);
Kmeans Kmean = new Kmeans(cellMetric.To1DArray(), numOfClusters, means.To1DArray());
// The corresponding sub-grid IDs
int[] subGridCellToClusterMap = Kmean.Cluster();
int[] noOfCellsPerCluster = Kmean.ClusterCount;
unsafe {
int[] globalCC = new int[numOfClusters];
// send = means[]
// receive = globalMeans[]
fixed(int *pSend = &noOfCellsPerCluster[0], pRcv = &globalCC[0])
{
csMPI.Raw.Allreduce((IntPtr)(pSend), (IntPtr)(pRcv), numOfClusters, csMPI.Raw._DATATYPE.INT, csMPI.Raw._OP.SUM, csMPI.Raw._COMM.WORLD);
}
noOfCellsPerCluster = globalCC;
}
int counter = numOfClusters;
for (int i = 0; i < numOfClusters; i++)
{
if (noOfCellsPerCluster[i] == 0)
{
System.Console.WriteLine("Sub-grid/Cluster " + (i + 1) + ", with mean value " + Kmean.Means[i] + ", is empty and not used anymore!");
counter--;
}
}
// Generating BitArray for all Subgrids, even for those which are empty, i.e ClusterCount == 0
BitArray[] baMatrix = new BitArray[numOfClusters];
for (int i = 0; i < numOfClusters; i++)
{
//baMatrix[i] = new BitArray(gridData.iLogicalCells.NoOfCells);
baMatrix[i] = new BitArray(gridData.iLogicalCells.NoOfLocalUpdatedCells);
}
// Filling the BitArrays
for (int i = 0; i < numOfCells; i++)
{
baMatrix[subGridCellToClusterMap[i]][subGrid.SubgridIndex2LocalCellIndex[i]] = true;
}
// Generating the sub-grids
List <SubGrid> clusters = new List <SubGrid>(counter);
for (int i = 0; i < numOfClusters; i++)
{
// Generating only the sub-grids which are not empty
if (noOfCellsPerCluster[i] != 0)
{
BitArray ba = baMatrix[i];
clusters.Add(new SubGrid(new CellMask(gridData, ba)));
}
}
return(new Clustering(clusters, subGrid));
}
/// <summary>
/// Creates the sub-grids of the clustering
/// </summary>
/// <param name="numOfClusters">Number of clusters</param>
/// <returns>A list of sub-grids</returns>
public Clustering CreateClustering(int numOfClusters, IList <TimeStepConstraint> timeStepConstraints, SubGrid subGrid = null)
{
//using (var tr = new ilPSP.Tracing.FuncTrace()) {
if (subGrid == null)
{
subGrid = new SubGrid(CellMask.GetFullMask(gridData));
}
// Attention: numOfCells can equal all local cells or only the local cells of a subgrid,
// e.g., the fluid cells in an IBM simulation
int numOfCells = subGrid.LocalNoOfCells;
MultidimensionalArray cellMetric = GetStableTimestepSize(subGrid, timeStepConstraints);
MultidimensionalArray means = CreateInitialMeans(cellMetric, numOfClusters);
Kmeans Kmean = new Kmeans(cellMetric.To1DArray(), numOfClusters, means.To1DArray());
// The corresponding sub-grid IDs
int[] subGridCellToClusterMap = Kmean.Cluster();
int[] noOfCellsPerCluster = Kmean.ClusterCount;
unsafe {
int[] globalCC = new int[numOfClusters];
// send = means[]
// receive = globalMeans[]
fixed(int *pSend = &noOfCellsPerCluster[0], pRcv = &globalCC[0])
{
csMPI.Raw.Allreduce((IntPtr)(pSend), (IntPtr)(pRcv), numOfClusters, csMPI.Raw._DATATYPE.INT, csMPI.Raw._OP.SUM, csMPI.Raw._COMM.WORLD);
}
noOfCellsPerCluster = globalCC;
}
int counter = numOfClusters;
for (int i = 0; i < numOfClusters; i++)
{
if (noOfCellsPerCluster[i] == 0)
{
if (consoleOutput)
{
Console.WriteLine("Sub-grid/Cluster " + (i + 1) + ", with mean value " + Kmean.Means[i] + ", is empty and not used anymore!");
}
counter--;
}
}
// Generating BitArray for all Subgrids, even for those which are empty, i.e ClusterCount == 0
BitArray[] baMatrix = new BitArray[numOfClusters];
for (int i = 0; i < numOfClusters; i++)
{
//baMatrix[i] = new BitArray(gridData.iLogicalCells.NoOfCells);
baMatrix[i] = new BitArray(gridData.iLogicalCells.NoOfLocalUpdatedCells);
}
// Filling the BitArrays
for (int i = 0; i < numOfCells; i++)
{
baMatrix[subGridCellToClusterMap[i]][subGrid.SubgridIndex2LocalCellIndex[i]] = true;
}
// IBM source cells are assigned to the cluster of the corresponding target cells
// This code is only excuted in IBM simulation runs
if (this.cellAgglomerator != null)
{
// MPI exchange in order to get cellToClusterMap (local + external cells)
int JE = gridData.iLogicalCells.Count;
int J = gridData.iLogicalCells.NoOfLocalUpdatedCells;
int[] cellToClusterMap = new int[JE];
int JSub = subGrid.LocalNoOfCells;
int[] jSub2j = subGrid.SubgridIndex2LocalCellIndex;
for (int jsub = 0; jsub < JSub; jsub++)
{
cellToClusterMap[jSub2j[jsub]] = subGridCellToClusterMap[jsub];
}
cellToClusterMap.MPIExchange(gridData);
foreach (AgglomerationPair aggPair in this.cellAgglomerator.AggInfo.AgglomerationPairs)
{
// AgglomerationPairs can contain combinations where jCellSource is on one MPI rank
// and the corresponding target cell is on another MPI rank. These duplications have to be eleminated.
if (aggPair.jCellSource < J)
{
// Assign source cell to the cluster of the corresponding target cell
int clusterOfTargetCell = cellToClusterMap[aggPair.jCellTarget];
baMatrix[clusterOfTargetCell][aggPair.jCellSource] = true;
// Delete source cell from other clusters
for (int j = 0; j < numOfClusters; j++)
{
if (clusterOfTargetCell != j)
{
baMatrix[j][aggPair.jCellSource] = false;
}
}
}
}
}
// Generating the sub-grids
List <SubGrid> clusters = new List <SubGrid>(counter);
for (int i = 0; i < numOfClusters; i++)
{
// Generating only the sub-grids which are not empty
if (noOfCellsPerCluster[i] != 0)
{
BitArray ba = baMatrix[i];
clusters.Add(new SubGrid(new CellMask(gridData, ba)));
}
}
if (consoleOutput)
{
for (int i = 0; i < clusters.Count; i++)
{
Console.WriteLine("CreateClustering:\t id=" + i + " ->\t\telements=" + clusters[i].GlobalNoOfCells);
}
}
return(new Clustering(clusters, subGrid));
}
