/* Computes the approximate Schur complement for the wide separator
using guided probing*/
Teuchos::RCP<Epetra_CrsMatrix> computeSchur_GuidedProbing
(
shylu_config *config,
shylu_symbolic *ssym, // symbolic structure
shylu_data *data, // numeric structure
Epetra_Map *localDRowMap
)
{
int i;
double relative_thres = config->relative_threshold;
Epetra_CrsMatrix *G = ssym->G.getRawPtr();
Epetra_CrsMatrix *R = ssym->R.getRawPtr();
Epetra_LinearProblem *LP = ssym->LP.getRawPtr();
Amesos_BaseSolver *solver = ssym->Solver.getRawPtr();
Ifpack_Preconditioner *ifSolver = ssym->ifSolver.getRawPtr();
Epetra_CrsMatrix *C = ssym->C.getRawPtr();
// Need to create local G (block diagonal portion) , R, C
// Get row map of G
Epetra_Map CrMap = C->RowMap();
int *c_rows = CrMap.MyGlobalElements();
int *c_cols = (C->ColMap()).MyGlobalElements();
//int c_totalElems = CrMap.NumGlobalElements();
int c_localElems = CrMap.NumMyElements();
int c_localcolElems = (C->ColMap()).NumMyElements();
Epetra_Map GrMap = G->RowMap();
int *g_rows = GrMap.MyGlobalElements();
//int g_totalElems = GrMap.NumGlobalElements();
int g_localElems = GrMap.NumMyElements();
Epetra_Map RrMap = R->RowMap();
int *r_rows = RrMap.MyGlobalElements();
int *r_cols = (R->ColMap()).MyGlobalElements();
//int r_totalElems = RrMap.NumGlobalElements();
int r_localElems = RrMap.NumMyElements();
int r_localcolElems = (R->ColMap()).NumMyElements();
Epetra_SerialComm LComm;
Epetra_Map C_localRMap (-1, c_localElems, c_rows, 0, LComm);
Epetra_Map C_localCMap (-1, c_localcolElems, c_cols, 0, LComm);
Epetra_Map G_localRMap (-1, g_localElems, g_rows, 0, LComm);
Epetra_Map R_localRMap (-1, r_localElems, r_rows, 0, LComm);
Epetra_Map R_localCMap (-1, r_localcolElems, r_cols, 0, LComm);
//cout << "#local rows" << g_localElems << "#non zero local cols" << c_localcolElems << endl;
#ifdef DEBUG
cout << "DEBUG MODE" << endl;
int nrows = C->RowMap().NumMyElements();
assert(nrows == localDRowMap->NumGlobalElements());
int gids[nrows], gids1[nrows];
C_localRMap.MyGlobalElements(gids);
localDRowMap->MyGlobalElements(gids1);
cout << "Comparing R's domain map with D's row map" << endl;
for (int i = 0; i < nrows; i++)
{
assert(gids[i] == gids1[i]);
}
#endif
int nentries1, gid;
// maxentries is the maximum of all three possible matrices as the arrays
// are reused between the three
int maxentries = max(C->MaxNumEntries(), R->MaxNumEntries());
maxentries = max(maxentries, G->MaxNumEntries());
double *values1 = new double[maxentries];
double *values2 = new double[maxentries];
double *values3 = new double[maxentries];
int *indices1 = new int[maxentries];
int *indices2 = new int[maxentries];
int *indices3 = new int[maxentries];
//cout << "Creating local matrices" << endl;
int err;
Epetra_CrsMatrix localC(Copy, C_localRMap, C->MaxNumEntries(), false);
for (i = 0; i < c_localElems ; i++)
{
gid = c_rows[i];
err = C->ExtractGlobalRowCopy(gid, maxentries, nentries1, values1,
indices1);
assert (err == 0);
//if (nentries1 > 0) // TODO: Later
//{
err = localC.InsertGlobalValues(gid, nentries1, values1, indices1);
assert (err == 0);
//}
}
localC.FillComplete(G_localRMap, C_localRMap);
//cout << "Created local C matrix" << endl;
Epetra_CrsMatrix localR(Copy, R_localRMap, R->MaxNumEntries(), false);
for (i = 0; i < r_localElems ; i++)
{
gid = r_rows[i];
R->ExtractGlobalRowCopy(gid, maxentries, nentries1, values1, indices1);
localR.InsertGlobalValues(gid, nentries1, values1, indices1);
}
localR.FillComplete(*localDRowMap, R_localRMap);
//cout << "Created local R matrix" << endl;
// Sbar - Approximate Schur complement
Teuchos::RCP<Epetra_CrsMatrix> Sbar = Teuchos::rcp(new Epetra_CrsMatrix(
Copy, GrMap, g_localElems));
// Include only the block diagonal elements of G in localG
Epetra_CrsMatrix localG(Copy, G_localRMap, G->MaxNumEntries(), false);
int cnt, scnt;
for (i = 0; i < g_localElems ; i++)
{
gid = g_rows[i];
G->ExtractGlobalRowCopy(gid, maxentries, nentries1, values1, indices1);
cnt = 0;
scnt = 0;
for (int j = 0 ; j < nentries1 ; j++)
{
if (G->LRID(indices1[j]) != -1)
{
values2[cnt] = values1[j];
indices2[cnt++] = indices1[j];
}
else
{
// Add it to Sbar immediately
values3[scnt] = values1[j];
indices3[scnt++] = indices1[j];
}
}
localG.InsertGlobalValues(gid, cnt, values2, indices2);
Sbar->InsertGlobalValues(gid, scnt, values3, indices3);
}
localG.FillComplete();
cout << "Created local G matrix" << endl;
int nvectors = 16;
ShyLU_Probing_Operator probeop(config, ssym, &localG, &localR, LP, solver,
ifSolver, &localC, localDRowMap, nvectors);
#ifdef DUMP_MATRICES
//ostringstream fnamestr;
//fnamestr << "localC" << C->Comm().MyPID() << ".mat";
//string Cfname = fnamestr.str();
//EpetraExt::RowMatrixToMatlabFile(Cfname.c_str(), localC);
//Epetra_Map defMapg(-1, g_localElems, 0, localG.Comm());
//EpetraExt::ViewTransform<Epetra_CrsMatrix> * ReIdx_MatTransg =
//new EpetraExt::CrsMatrix_Reindex( defMapg );
//Epetra_CrsMatrix t2G = (*ReIdx_MatTransg)( localG );
//ReIdx_MatTransg->fwd();
//EpetraExt::RowMatrixToMatlabFile("localG.mat", t2G);
#endif
//cout << " totalElems in Schur Complement" << totalElems << endl;
//cout << myPID << " localElems" << localElems << endl;
// **************** Two collectives here *********************
#ifdef TIMING_OUTPUT
Teuchos::Time ftime("setup time");
#endif
#ifdef TIMING_OUTPUT
Teuchos::Time app_time("setup time");
#endif
Teuchos::RCP<Epetra_CrsGraph> lSGraph = Teuchos::RCP<Epetra_CrsGraph> (
new Epetra_CrsGraph(Copy, G_localRMap, maxentries));
if (data->num_compute % config->reset_iter == 0)
{
int nentries;
// size > maxentries as there could be fill
// TODO: Currently the size of the two arrays can be one, Even if we switch
// the loop below the size of the array required is nvectors. Fix it
double *values = new double[g_localElems];
int *indices = new int[g_localElems];
double *vecvalues;
int dropped = 0;
double *maxvalue = new double[nvectors];
#ifdef TIMING_OUTPUT
ftime.start();
#endif
int findex = g_localElems / nvectors ;
int cindex;
// int mypid = C->Comm().MyPID(); // unused
Epetra_MultiVector probevec(G_localRMap, nvectors);
Epetra_MultiVector Scol(G_localRMap, nvectors);
for (i = 0 ; i < findex*nvectors ; i+=nvectors)
{
probevec.PutScalar(0.0); // TODO: Move it out
for (int k = 0; k < nvectors; k++)
{
cindex = k+i;
// TODO: Can do better than this, just need to go to the column map
// of C, there might be null columns in C
// Not much of use for Shasta 2x2 .. Later.
probevec.ReplaceGlobalValue(g_rows[cindex], k, 1.0);
//if (mypid == 0)
//cout << "Changing row to 1.0 " << g_rows[cindex] << endl;
}
#ifdef TIMING_OUTPUT
app_time.start();
#endif
probeop.Apply(probevec, Scol);
#ifdef TIMING_OUTPUT
app_time.stop();
#endif
Scol.MaxValue(maxvalue);
for (int k = 0; k < nvectors; k++) //TODO:Need to switch these loops
{
cindex = k+i;
vecvalues = Scol[k];
//cout << "MAX" << maxvalue << endl;
for (int j = 0 ; j < g_localElems ; j++)
{
nentries = 0; // inserting one entry in each row for now
if (g_rows[cindex] == g_rows[j]) // diagonal entry
{
values[nentries] = vecvalues[j];
indices[nentries] = g_rows[cindex];
nentries++;
err = Sbar->InsertGlobalValues(g_rows[j], nentries, values,
indices);
assert(err >= 0);
err = lSGraph->InsertGlobalIndices(g_rows[j], nentries,
indices);
assert(err >= 0);
}
else if (abs(vecvalues[j]/maxvalue[k]) > relative_thres)
{
values[nentries] = vecvalues[j];
indices[nentries] = g_rows[cindex];
nentries++;
err = Sbar->InsertGlobalValues(g_rows[j], nentries, values,
indices);
assert(err >= 0);
err = lSGraph->InsertGlobalIndices(g_rows[j], nentries,
indices);
assert(err >= 0);
}
else
{
if (vecvalues[j] != 0.0)
{
dropped++;
//cout << "vecvalues[j]" << vecvalues[j] <<
// " max" << maxvalue[k] << endl;
}
}
}
}
}
probeop.ResetTempVectors(1);
for ( ; i < g_localElems ; i++)
{
// TODO: Can move the next two decalarations outside the loop
Epetra_MultiVector probevec(G_localRMap, 1);
Epetra_MultiVector Scol(G_localRMap, 1);
probevec.PutScalar(0.0);
// TODO: Can do better than this, just need to go to the column map
// of C, there might be null columns in C
probevec.ReplaceGlobalValue(g_rows[i], 0, 1.0);
#ifdef TIMING_OUTPUT
app_time.start();
#endif
probeop.Apply(probevec, Scol);
#ifdef TIMING_OUTPUT
app_time.stop();
#endif
vecvalues = Scol[0];
Scol.MaxValue(maxvalue);
//cout << "MAX" << maxvalue << endl;
for (int j = 0 ; j < g_localElems ; j++)
{
nentries = 0; // inserting one entry in each row for now
if (g_rows[i] == g_rows[j]) // diagonal entry
{
values[nentries] = vecvalues[j];
indices[nentries] = g_rows[i];
nentries++;
err = Sbar->InsertGlobalValues(g_rows[j], nentries, values, indices);
assert(err >= 0);
err = lSGraph->InsertGlobalIndices(g_rows[j], nentries, indices);
assert(err >= 0);
}
else if (abs(vecvalues[j]/maxvalue[0]) > relative_thres)
{
values[nentries] = vecvalues[j];
indices[nentries] = g_rows[i];
nentries++;
err = Sbar->InsertGlobalValues(g_rows[j], nentries, values, indices);
assert(err >= 0);
err = lSGraph->InsertGlobalIndices(g_rows[j], nentries, indices);
assert(err >= 0);
}
else
{
if (vecvalues[j] != 0.0) dropped++;
}
}
}
#ifdef TIMING_OUTPUT
ftime.stop();
cout << "Time in finding and dropping entries" << ftime.totalElapsedTime() << endl;
ftime.reset();
#endif
#ifdef TIMING_OUTPUT
cout << "Time in Apply of probing" << app_time.totalElapsedTime() << endl;
#endif
probeop.PrintTimingInfo();
Sbar->FillComplete();
lSGraph->FillComplete();
data->localSbargraph = lSGraph;
#ifdef DUMP_MATRICES
Epetra_Map defMap2(-1, g_localElems, 0, C->Comm());
EpetraExt::ViewTransform<Epetra_CrsMatrix> * ReIdx_MatTrans2 =
new EpetraExt::CrsMatrix_Reindex( defMap2 );
Epetra_CrsMatrix t2S = (*ReIdx_MatTrans2)( *Sbar );
ReIdx_MatTrans2->fwd();
EpetraExt::RowMatrixToMatlabFile("Schur.mat", t2S);
#endif
cout << "#dropped entries" << dropped << endl;
delete[] values;
delete[] indices;
delete[] maxvalue;
}
else
{
if (((data->num_compute-1) % config->reset_iter) == 0)
{
// We recomputed the Schur complement with dropping for the last
// compute. Reset the prober with the new orthogonal vectors for
// the Sbar from the previous iteration.
Teuchos::ParameterList pList;
Teuchos::RCP<Isorropia::Epetra::Prober> gprober =
Teuchos::RCP<Isorropia::Epetra::Prober> (new
Isorropia::Epetra::Prober(
data->localSbargraph.getRawPtr(), pList, false));
gprober->color();
data->guided_prober = gprober;
}
// Use the prober to probe the probeop for the sparsity pattern
// add that to Sbar and call Fill complete
int nvectors = data->guided_prober->getNumOrthogonalVectors();
cout << "Number of Orthogonal Vectors for guided probing" << nvectors
<< endl;
probeop.ResetTempVectors(nvectors);
Teuchos::RCP<Epetra_CrsMatrix> blockdiag_Sbar =
data->guided_prober->probe(probeop);
int maxentries = blockdiag_Sbar->GlobalMaxNumEntries();
int *indices = new int[maxentries];
double *values = new double[maxentries];
int numentries;
for (int i = 0; i < blockdiag_Sbar->NumGlobalRows() ; i++)
{
int gid = blockdiag_Sbar->GRID(i);
blockdiag_Sbar->ExtractGlobalRowCopy(gid, maxentries, numentries,
values, indices);
Sbar->InsertGlobalValues(gid, numentries, values, indices);
}
Sbar->FillComplete();
delete[] indices;
delete[] values;
}
delete[] values1;
delete[] indices1;
delete[] values2;
delete[] indices2;
delete[] values3;
delete[] indices3;
return Sbar;
}
