public void Init(MultigridOperator op)
{
using (new FuncTrace()) {
if (m_MgOp != null)
{
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// someone is trying to re-use this solver: see if the settings permit that
// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
if (op.LevelIndex != m_MgOp.LevelIndex)
{
throw new ArgumentException("Re-use on different level not possible.");
}
if (!this.MtxFull._RowPartitioning.EqualsPartition(op.OperatorMatrix._RowPartitioning))
{
throw new ArgumentException("Matrix has changed, unable to re-use");
}
if (!this.MtxFull._ColPartitioning.EqualsPartition(op.OperatorMatrix._ColPartitioning))
{
throw new ArgumentException("Matrix has changed, unable to re-use");
}
#if DEBUG
if (!object.ReferenceEquals(this.MtxFull, op.OperatorMatrix))
{
BlockMsrMatrix Check = this.MtxFull.CloneAs();
Check.Acc(-1.0, op.OperatorMatrix);
if (Check.InfNorm() != 0.0)
{
throw new ArgumentException("Matrix has changed, unable to re-use");
}
}
#endif
if (this.m_BlockingStrategy.GetNoOfBlocks(op) != this.blockSolvers.Count())
{
throw new ArgumentException("Blocking, unable to re-use");
}
return;
}
var Mop = op.OperatorMatrix;
var MgMap = op.Mapping;
this.m_MgOp = op;
int myMpiRank = MgMap.MpiRank;
int myMpisize = MgMap.MpiSize;
if (!Mop.RowPartitioning.EqualsPartition(MgMap.Partitioning))
{
throw new ArgumentException("Row partitioning mismatch.");
}
if (!Mop.ColPartition.EqualsPartition(MgMap.Partitioning))
{
throw new ArgumentException("Column partitioning mismatch.");
}
var ag = MgMap.AggGrid;
int JComp = ag.iLogicalCells.NoOfLocalUpdatedCells;
int JGhost = ag.iLogicalCells.NoOfExternalCells;
#if DEBUG
ilPSP.Connectors.Matlab.BatchmodeConnector matlab;
if (m_MatlabParalellizationCheck)
{
matlab = new ilPSP.Connectors.Matlab.BatchmodeConnector();
}
else
{
matlab = null;
}
#endif
//Mop.Clear();
//for(int i = Mop.RowPartitioning.i0; i < Mop.RowPartitioning.iE; i++) {
// Mop[i, i] = i + 1;
//}
// get cell blocks
// ===============
var _Blocks = this.m_BlockingStrategy.GetBlocking(op);
int NoOfSchwzBlocks = _Blocks.Count();
// test cell blocks
// ================
#if DEBUG
{
// ensure that each cell is used exactly once, among all blocks
bool[] test = new bool[ag.iLogicalCells.NoOfLocalUpdatedCells];
foreach (var bi in _Blocks)
{
foreach (int j in bi)
{
Debug.Assert(test[j] == false);
test[j] = true;
}
;
}
for (int i = 0; i < test.Length; i++)
{
Debug.Assert(test[i] == true);
}
}
#endif
// extend blocks according to desired overlap
// ==========================================
{
BitArray marker = new BitArray(JComp + JGhost);
if (Overlap < 0)
{
throw new ArgumentException();
}
if (Overlap > 0)
{
if (Overlap > 1 && Mop.RowPartitioning.MpiSize > 1)
{
throw new NotSupportedException("In MPI parallel runs, the maximum supported overlap for the Schwarz preconditioner is 1.");
}
foreach (List <int> bi in _Blocks) // loop over blocks...
{
marker.SetAll(false); // marks all cells which are members of the block
foreach (int jcomp in bi)
{
marker[jcomp] = true;
}
// determine overlap regions
for (int k = 0; k < Overlap; k++)
{
int Jblock = bi.Count;
for (int j = 0; j < Jblock; j++)
{
int jCell = bi[j];
int[] Neighs = ag.iLogicalCells.CellNeighbours[jCell];
foreach (int jNeigh in Neighs)
{
if (marker[jNeigh] == false)
{
// neighbor cell is not already a member of the block
// => add it.
bi.Add(jNeigh);
marker[jNeigh] = true;
}
}
}
}
bi.Sort();
}
}
BlockCells = _Blocks.Select(list => list.ToArray()).ToArray();
}
// convert cell blocks to DOF blocks
// =================================
List <int>[] BlkIdx_gI_lR; // for each Schwarz block, (global) indices in the local range
List <int>[] BlkIdx_gI_eR; // for each Schwarz block, (global) indices of external rows and columns
List <int>[] TempRowIdx_gI; // for each Schwarz block, (global) indices into the temporary matrix
List <int>[] BlkIdx_lI_eR; // for each Schwarz block, (local) indices of external rows and columns
List <int>[] LocalBlocks_i0, LocalBlocks_N; // blocking of the Schwarz-Blocks.
// for matrix 'ExternalRowsTemp': which rows of 'Mop' are required locally
List <int> ExternalRowsIndices, ExternalRows_BlockI0, ExternalRows_BlockN;
{
int Jup = MgMap.AggGrid.iLogicalCells.NoOfLocalUpdatedCells;
int Jgh = MgMap.AggGrid.iLogicalCells.NoOfExternalCells;
int LocalizedBlockCounter = 0;
BlkIdx_gI_lR = NoOfSchwzBlocks.ForLoop(iPart => new List <int>(BlockCells[iPart].Length * MgMap.MaximalLength));
BlkIdx_gI_eR = NoOfSchwzBlocks.ForLoop(iPart => new List <int>());
LocalBlocks_i0 = NoOfSchwzBlocks.ForLoop(iPart => new List <int>());
LocalBlocks_N = NoOfSchwzBlocks.ForLoop(iPart => new List <int>());
TempRowIdx_gI = NoOfSchwzBlocks.ForLoop(iPart => new List <int>());
BlkIdx_lI_eR = NoOfSchwzBlocks.ForLoop(iPart => new List <int>());
ExternalRowsIndices = new List <int>();
ExternalRows_BlockI0 = new List <int>();
ExternalRows_BlockN = new List <int>();
for (int iPart = 0; iPart < NoOfSchwzBlocks; iPart++) // loop over parts...
{
int[] bc = BlockCells[iPart];
var biI = BlkIdx_gI_lR[iPart];
var biE = BlkIdx_gI_eR[iPart];
var l1 = TempRowIdx_gI[iPart];
var l2 = BlkIdx_lI_eR[iPart];
var LBBi0 = LocalBlocks_i0[iPart];
var LBBN = LocalBlocks_N[iPart];
int Jblock = bc.Length;
int anotherCounter = 0;
for (int jblk = 0; jblk < Jblock; jblk++) // loop over cells in blocks...
{
int j = bc[jblk];
int N = MgMap.GetLength(j);
if (j < Jup)
{
// locally updated cell
int i0 = MgMap.GlobalUniqueIndex(0, j, 0);
for (int n = 0; n < N; n++)
{
biI.Add(i0 + n);
}
}
else
{
// external cell
int i0E = MgMap.GlobalUniqueIndex(0, j, 0); //
int i0L = MgMap.LocalUniqueIndex(0, j, 0); //
ExternalRows_BlockI0.Add(LocalizedBlockCounter);
ExternalRows_BlockN.Add(N);
//LEBi0.Add(LocalizedBlockCounter);
//LEBn.Add(N);
for (int n = 0; n < N; n++)
{
biE.Add(i0E + n);
ExternalRowsIndices.Add(i0E + n);
l1.Add(LocalizedBlockCounter + n);
l2.Add(i0L + n);
Debug.Assert(Mop._RowPartitioning.FindProcess(i0E + n) != myMpiRank);
}
LocalizedBlockCounter += N;
}
LBBi0.Add(anotherCounter);
LBBN.Add(N);
anotherCounter += N;
}
}
//this.BlockIndices = _LocallyStoredBlockIndices.Select(bi => bi.ToArray()).ToArray();
}
// get rows for blocks that use external cells
// ===========================================
#if DEBUG
{
if (Overlap == 0)
{
Debug.Assert(ExternalRowsIndices.Count == 0);
Debug.Assert(ExternalRows_BlockI0.Count == 0);
Debug.Assert(ExternalRows_BlockN.Count == 0);
}
foreach (var bi in BlkIdx_gI_lR)
{
foreach (int idx in bi)
{
Debug.Assert(idx >= m_MgOp.Mapping.i0);
Debug.Assert(idx < m_MgOp.Mapping.iE);
}
}
foreach (var ei in BlkIdx_gI_eR)
{
foreach (int idx in ei)
{
Debug.Assert(idx < m_MgOp.Mapping.i0 || idx >= m_MgOp.Mapping.iE);
}
}
int LL = m_MgOp.Mapping.LocalLength;
int jMax = m_MgOp.Mapping.AggGrid.iLogicalCells.NoOfCells - 1;
int LE = m_MgOp.Mapping.LocalUniqueIndex(0, jMax, 0) + m_MgOp.Mapping.GetLength(jMax);
foreach (var ci in BlkIdx_lI_eR)
{
foreach (int idx in ci)
{
Debug.Assert(idx >= LL);
Debug.Assert(idx < LE);
}
}
if (m_MatlabParalellizationCheck)
{
int globalBlockCounter = 0;
for (int rankCounter = 0; rankCounter < myMpisize; rankCounter++)
{
int rank_NoBlks = NoOfSchwzBlocks.MPIBroadcast(rankCounter);
if (rankCounter == myMpiRank)
{
Debug.Assert(rank_NoBlks == NoOfSchwzBlocks);
}
for (int iBlock = 0; iBlock < rank_NoBlks; iBlock++)
{
double[] vec;
if (rankCounter == myMpiRank)
{
vec = ArrayTools.Cat(BlkIdx_gI_lR[iBlock], BlkIdx_gI_eR[iBlock]).Select(ii => ((double)(ii + 1))).ToArray();
}
else
{
vec = new double[0];
}
matlab.PutVector(vec, string.Format("BlockIdx{0}", globalBlockCounter));
globalBlockCounter++;
csMPI.Raw.Barrier(csMPI.Raw._COMM.WORLD);
}
}
}
}
#endif
BlockMsrMatrix ExternalRowsTemp;
if (myMpisize > 1 && Overlap > 0)
{
//int NoOfLocalRows = _ExternalBlockIndices.Sum(L => L.Count);
BlockPartitioning PermRow = new BlockPartitioning(ExternalRowsIndices.Count, ExternalRows_BlockI0, ExternalRows_BlockN, Mop.MPI_Comm, i0isLocal: true);
// Remark: we use a permutation matrix for MPI-exchange of rows
BlockMsrMatrix Perm = new BlockMsrMatrix(PermRow, Mop._RowPartitioning);
for (int iRow = 0; iRow < ExternalRowsIndices.Count; iRow++)
{
Debug.Assert(Mop._RowPartitioning.IsInLocalRange(ExternalRowsIndices[iRow]) == false);
Perm[iRow + PermRow.i0, ExternalRowsIndices[iRow]] = 1;
}
ExternalRowsTemp = BlockMsrMatrix.Multiply(Perm, Mop);
#if DEBUG
if (m_MatlabParalellizationCheck)
{
matlab.PutSparseMatrix(Perm, "Perm");
matlab.PutSparseMatrix(ExternalRowsTemp, "ExternalRowsTemp");
}
#endif
}
else
{
ExternalRowsTemp = null;
}
ExternalRowsIndices = null;
ExternalRows_BlockI0 = null;
ExternalRows_BlockN = null;
// create solvers
// ==============
{
blockSolvers = new ISparseSolver[NoOfSchwzBlocks];
#if DEBUG
List <BlockMsrMatrix> Blocks = new List <BlockMsrMatrix>();
#endif
for (int iPart = 0; iPart < NoOfSchwzBlocks; iPart++)
{
var bi = BlkIdx_gI_lR[iPart];
int Bsz;
if (MgMap.MinimalLength == MgMap.MaximalLength)
{
Bsz = MgMap.MaximalLength;
}
else
{
Bsz = 1;
}
var l1 = TempRowIdx_gI[iPart];
//if (M.RowPartitioning.MpiSize > 1) {
// int i0Proc = M.RowPartitioning.i0;
// bi = bi.CloneAs();
// for (int i = 0; i < bi.Length; i++) {
// bi[i] += i0Proc;
// }
//}
BlockPartitioning localBlocking = new BlockPartitioning(bi.Count + l1.Count, LocalBlocks_i0[iPart], LocalBlocks_N[iPart], csMPI.Raw._COMM.SELF);
if (l1.Count > 0)
{
// convert the indices into 'ExternalRowsTemp' to global indices
int l1L = l1.Count;
int offset = ExternalRowsTemp._RowPartitioning.i0;
for (int i = 0; i < l1L; i++)
{
l1[i] += offset;
}
}
BlockMsrMatrix Block = new BlockMsrMatrix(localBlocking, localBlocking);// bi.Length, bi.Length, Bsz, Bsz);
Mop.WriteSubMatrixTo(Block, bi, default(int[]), bi, default(int[]));
if (l1.Count > 0)
{
int offset = bi.Count;
int[] targRows = l1.Count.ForLoop(i => i + offset);
var biE = BlkIdx_gI_eR[iPart];
int[] extTargCols = biE.Count.ForLoop(i => i + offset);
Mop.AccSubMatrixTo(1.0, Block, bi, default(int[]), new int[0], default(int[]), biE, extTargCols);
ExternalRowsTemp.AccSubMatrixTo(1.0, Block, l1, targRows, bi, default(int[]), biE, extTargCols);
}
#if DEBUG
if (m_MatlabParalellizationCheck)
{
Blocks.Add(Block);
}
#endif
blockSolvers[iPart] = new PARDISOSolver()
{
CacheFactorization = true,
UseDoublePrecision = false
};
//blockSolvers[iPart] = new FullDirectSolver();
//blockSolvers[iPart] = new ilPSP.LinSolvers.MUMPS.MUMPSSolver();
blockSolvers[iPart].DefineMatrix(Block);
}
#if DEBUG
if (m_MatlabParalellizationCheck)
{
int globalBlockCounter = 0;
for (int rankCounter = 0; rankCounter < myMpisize; rankCounter++)
{
int rank_NoBlks = NoOfSchwzBlocks.MPIBroadcast(rankCounter);
for (int iBlock = 0; iBlock < rank_NoBlks; iBlock++)
{
BlockMsrMatrix Block;
if (rankCounter == myMpiRank)
{
Block = Blocks[iBlock];
}
else
{
Block = null;
}
matlab.PutSparseMatrix(Block, string.Format("Block{0}", globalBlockCounter));
globalBlockCounter++;
csMPI.Raw.Barrier(csMPI.Raw._COMM.WORLD);
}
}
}
#endif
}
// Record required indices
// =======================
{
this.BlockIndices_Local = new int[NoOfSchwzBlocks][];
this.BlockIndices_External = new int[NoOfSchwzBlocks][];
int LocalI0 = MgMap.i0;
int LocalLength = MgMap.LocalLength;
for (int iBlock = 0; iBlock < NoOfSchwzBlocks; iBlock++)
{
var _bi = BlkIdx_gI_lR[iBlock];
int L = _bi.Count;
int[] bil = new int[L];
this.BlockIndices_Local[iBlock] = bil;
for (int l = 0; l < L; l++)
{
bil[l] = _bi[l] - LocalI0;
Debug.Assert(bil[l] >= 0);
Debug.Assert(bil[l] < MgMap.LocalLength);
}
var _biE = BlkIdx_lI_eR[iBlock];
if (_biE.Count > 0)
{
this.BlockIndices_External[iBlock] = _biE.ToArray();
}
}
}
this.MtxFull = Mop;
if (CoarseSolver != null)
{
CoarseSolver.Init(op.CoarserLevel);
}
// Debug & Test-Code
// =================
#if DEBUG
if (m_MatlabParalellizationCheck)
{
Console.WriteLine("Matlab dir: " + matlab.WorkingDirectory);
matlab.PutSparseMatrix(Mop, "Full");
int GlobalNoOfBlocks = NoOfSchwzBlocks.MPISum();
for (int iGlbBlock = 0; iGlbBlock < GlobalNoOfBlocks; iGlbBlock++)
{
matlab.Cmd("BlockErr({0} + 1, 1) = norm( Block{0} - Full( BlockIdx{0}, BlockIdx{0} ), inf );", iGlbBlock);
}
Random rnd = new Random(myMpiRank);
double[] testRHS = new double[MgMap.LocalLength];
for (int i = 0; i < testRHS.Length; i++)
{
testRHS[i] = rnd.NextDouble();
}
matlab.PutVector(testRHS, "testRHS");
MPIexchange <double[]> ResExchange = new MPIexchange <double[]>(MgMap, testRHS);
ResExchange.TransceiveStartImReturn();
ResExchange.TransceiveFinish(0.0);
int offset = MgMap.LocalLength;
int g = 0;
for (int rankCounter = 0; rankCounter < myMpisize; rankCounter++)
{
int rank_NoBlks = NoOfSchwzBlocks.MPIBroadcast(rankCounter);
for (int iBlock = 0; iBlock < rank_NoBlks; iBlock++)
{
double[] SubVec;
if (rankCounter == myMpiRank)
{
int LL = this.BlockIndices_Local[iBlock].Length;
int LE;
if (this.BlockIndices_External[iBlock] != null)
{
LE = this.BlockIndices_External[iBlock].Length;
}
else
{
LE = 0;
}
int L = LL + LE;
SubVec = new double[L];
for (int i = 0; i < LL; i++)
{
SubVec[i] = testRHS[this.BlockIndices_Local[iBlock][i]];
}
if (LE > 0)
{
for (int i = 0; i < LE; i++)
{
SubVec[i + LL] = ResExchange.Vector_Ext[this.BlockIndices_External[iBlock][i] - offset];
}
}
}
else
{
SubVec = new double[0];
}
matlab.PutVector(SubVec, "SubVec" + g);
g++;
}
}
for (int iGlbBlock = 0; iGlbBlock < GlobalNoOfBlocks; iGlbBlock++)
{
matlab.Cmd("RhsErr({0} + 1, 1) = norm( SubVec{0} - testRHS( BlockIdx{0} ), inf );", iGlbBlock);
}
double[] testX = new double[testRHS.Length];
MPIexchangeInverse <double[]> XExchange = new MPIexchangeInverse <double[]>(MgMap, testX);
g = 0;
for (int rankCounter = 0; rankCounter < myMpisize; rankCounter++)
{
int rank_NoBlks = NoOfSchwzBlocks.MPIBroadcast(rankCounter);
for (int iBlock = 0; iBlock < rank_NoBlks; iBlock++)
{
if (rankCounter == myMpiRank)
{
int LL = this.BlockIndices_Local[iBlock].Length;
int LE;
if (this.BlockIndices_External[iBlock] != null)
{
LE = this.BlockIndices_External[iBlock].Length;
}
else
{
LE = 0;
}
int L = LL + LE;
for (int i = 0; i < LL; i++)
{
testX[this.BlockIndices_Local[iBlock][i]] += (g + 1);
}
if (LE > 0)
{
for (int i = 0; i < LE; i++)
{
XExchange.Vector_Ext[this.BlockIndices_External[iBlock][i] - offset] += (g + 1);
}
}
}
else
{
//nop
}
g++;
}
}
XExchange.TransceiveStartImReturn();
XExchange.TransceiveFinish(1.0);
matlab.Cmd("testXref = zeros({0},1);", MgMap.TotalLength);
for (int iGlbBlock = 0; iGlbBlock < GlobalNoOfBlocks; iGlbBlock++)
{
matlab.Cmd("testXref(BlockIdx{0},1) = testXref(BlockIdx{0},1) + ({0} + 1);", iGlbBlock);
}
matlab.PutVector(testX, "testX");
matlab.Cmd("testXErr = norm(testX - testXref, inf);");
MultidimensionalArray BlockErr = MultidimensionalArray.Create(GlobalNoOfBlocks, 1);
MultidimensionalArray RhsErr = MultidimensionalArray.Create(GlobalNoOfBlocks, 1);
MultidimensionalArray testXErr = MultidimensionalArray.Create(1, 1);
matlab.GetMatrix(BlockErr, "BlockErr");
matlab.GetMatrix(RhsErr, "RhsErr");
matlab.GetMatrix(testXErr, "testXErr");
matlab.Execute();
for (int iGlbBlock = 0; iGlbBlock < GlobalNoOfBlocks; iGlbBlock++)
{
Console.WriteLine("Block #{0} Error (external? ) " + BlockErr[iGlbBlock, 0], iGlbBlock);
Console.WriteLine("RHS #{0} Error " + RhsErr[iGlbBlock, 0], iGlbBlock);
Debug.Assert(BlockErr[iGlbBlock, 0] == 0);
Debug.Assert(RhsErr[iGlbBlock, 0] == 0);
}
Console.WriteLine("X Error " + testXErr[0, 0]);
Debug.Assert(testXErr[0, 0] == 0.0);
matlab.Dispose();
}
#endif
}
}
//static void SingleFilter(double[] V) {
// for(int i = 0; i < V.Length; i++) {
// float vi = (float)(V[i]);
// V[i] = vi;
// }
//}
public void Solve <U, V>(U X, V B)
where U : IList <double>
where V : IList <double> //
{
using (var tr = new FuncTrace()) {
int NoParts = this.BlockIndices_Local.Length;
// --------
// Reminder: we solve for a correction, the basic idea is:
//
// X0 is current solution, state of 'X' at input time
// Residual = B - M*X0;
// now solve (approximately)
// M*Xc = Residual,
// if we would solve exactly, i.e.
// Xc = M^{-1}*Residual
// then X=(X0+Xc) is an exact solution of
// M*X = B
// --------
double[] Res = new double[B.Count];
MPIexchange <double[]> ResExchange;
MPIexchangeInverse <U> XExchange;
if (Overlap > 0)
{
ResExchange = new MPIexchange <double[]>(this.m_MgOp.Mapping, Res);
XExchange = new MPIexchangeInverse <U>(this.m_MgOp.Mapping, X);
}
else
{
ResExchange = null;
XExchange = null;
#if DEBUG
foreach (var ciE in BlockIndices_External)
{
Debug.Assert(ciE == null || ciE.Length <= 0);
}
#endif
}
int LocLength = m_MgOp.Mapping.LocalLength;
for (int iIter = 0; iIter < m_MaxIterations; iIter++)
{
this.NoIter++;
Res.SetV(B);
this.MtxFull.SpMV(-1.0, X, 1.0, Res);
if (IterationCallback != null)
{
IterationCallback(iIter, X.ToArray(), Res.CloneAs(), this.m_MgOp);
}
using (new BlockTrace("coarse_solve_level" + this.m_MgOp.LevelIndex, tr)) {
if (CoarseSolver != null)
{
var XC = X.ToArray().CloneAs();
double[] bc = new double[m_MgOp.CoarserLevel.Mapping.LocalLength];// = Res.CloneAs();
m_MgOp.CoarserLevel.Restrict(Res.CloneAs(), bc);
double[] xc = new double[bc.Length];
CoarseSolver.Solve(xc, bc);
//SingleFilter(xc);
m_MgOp.CoarserLevel.Prolongate(1, XC, 1, xc);
X.AccV(1.0, XC);
if (CoarseSolverIsMultiplicative)
{
Res.SetV(B);
this.MtxFull.SpMV(-1.0, X, 1.0, Res);
}
}
}
if (Overlap > 0)
{
ResExchange.TransceiveStartImReturn();
ResExchange.TransceiveFinish(0.0);
}
using (new BlockTrace("block_solve_level" + this.m_MgOp.LevelIndex, tr)) {
for (int iPart = 0; iPart < NoParts; iPart++)
{
int[] ci = BlockIndices_Local[iPart];
int[] ciE = BlockIndices_External[iPart];
int L = ci.Length;
if (ciE != null)
{
L += ciE.Length;
}
double[] bi = new double[L];
double[] xi = new double[L];
// extract block part of residual
bi.AccV(1.0, Res, default(int[]), ci);
if (ciE != null && ciE.Length > 0)
{
bi.AccV(1.0, ResExchange.Vector_Ext, default(int[]), ciE, acc_index_shift: ci.Length, b_index_shift: (-LocLength));
}
blockSolvers[iPart].Solve(xi, bi);
//SingleFilter(xi);
// accumulate block solution 'xi' to global solution 'X'
X.AccV(1.0, xi, ci, default(int[]));
if (ciE != null && ciE.Length > 0)
{
XExchange.Vector_Ext.AccV(1.0, xi, ciE, default(int[]), acc_index_shift: (-LocLength), b_index_shift: ci.Length);
}
}
}
if (Overlap > 0)
{
// block solutions stored on *external* indices will be accumulated on other processors.
XExchange.TransceiveStartImReturn();
XExchange.TransceiveFinish(1.0);
if (iIter < m_MaxIterations - 1)
{
XExchange.Vector_Ext.ClearEntries();
}
}
}
}
}