SparseMatrix* FiniteElementSpace::NC_GlobalRestrictionMatrix
(FiniteElementSpace* cfes, NCMesh* ncmesh)
{
Array<int> rows, cols, rs, cs;
LinearFECollection linfec;
NCMesh::FineTransform* transforms = ncmesh->GetFineTransforms();
SparseMatrix* R = new SparseMatrix(cfes->GetVSize(), this->GetVSize());
// we mark each fine DOF the first time its column is set so that slave node
// values don't get represented twice in R
Array<int> mark(this->GetNDofs());
mark = 0;
// loop over the fine elements, get interpolations of the coarse elements
for (int k = 0; k < mesh->GetNE(); k++)
{
mesh->SetState(Mesh::TWO_LEVEL_COARSE);
cfes->GetElementDofs(transforms[k].coarse_index, rows);
mesh->SetState(Mesh::TWO_LEVEL_FINE);
this->GetElementDofs(k, cols);
if (!transforms[k].IsIdentity())
{
int geom = mesh->GetElementBaseGeometry(k);
const FiniteElement *fe = fec->FiniteElementForGeometry(geom);
IsoparametricTransformation trans;
trans.SetFE(linfec.FiniteElementForGeometry(geom));
trans.GetPointMat() = transforms[k].point_matrix;
DenseMatrix I(fe->GetDof());
fe->GetLocalInterpolation(trans, I);
// TODO: use std::unordered_map to cache I matrices (point_matrix as key)
// make sure we don't set any column of R more than once
for (int i = 0; i < I.Height(); i++)
{
int col = cols[i];
if (col < 0)
col = -1 - col;
if (mark[col]++)
I.SetRow(i, 0); // zero the i-th row of I
}
cfes->DofsToVDofs(rows);
this->DofsToVDofs(cols);
SetVDofSubMatrixTranspose(*R, rows, cols, I, vdim);
}
else // optimization: insert identity for elements that were not refined
{
MFEM_ASSERT(rows.Size() == cols.Size(), "");
for (int i = 0; i < rows.Size(); i++)
{
int col = cols[i];
if (col < 0)
col = -1 - col;
if (!mark[col]++)
for (int vd = 0; vd < vdim; vd++)
R->Set(cfes->DofToVDof(rows[i], vd),
this->DofToVDof(cols[i], vd), 1.0);
}
}
}
delete [] transforms;
return R;
}
