anonymous_namespace{EigenTools.cpp} Namespace Reference

Functions
void	setRowsToZeroOffDiagonal (MathLib::EigenMatrix::RawMatrixType &A_eigen, const std::vector< MathLib::EigenMatrix::IndexType > &row_ids)
void	applyKnownSolutionComplete (MathLib::EigenMatrix::RawMatrixType &A_eigen, MathLib::EigenVector::RawVectorType &b_eigen, const std::vector< MathLib::EigenMatrix::IndexType > &vec_knownX_id, const std::vector< double > &vec_knownX_x)
void	applyKnownSolutionIncomplete (MathLib::EigenMatrix::RawMatrixType &A_eigen, MathLib::EigenVector::RawVectorType &b_eigen, const std::vector< MathLib::EigenMatrix::IndexType > &vec_knownX_id, const std::vector< double > &vec_knownX_x)

Function Documentation

applyKnownSolutionComplete()

void anonymous_namespace{EigenTools.cpp}::applyKnownSolutionComplete	(	MathLib::EigenMatrix::RawMatrixType &	A_eigen,
		MathLib::EigenVector::RawVectorType &	b_eigen,
		const std::vector< MathLib::EigenMatrix::IndexType > &	vec_knownX_id,
		const std::vector< double > &	vec_knownX_x )

Definition at line 32 of file EigenTools.cpp.

{
    setRowsToZeroOffDiagonal(A_eigen, vec_knownX_id);
 
    using SpMat = MathLib::EigenMatrix::RawMatrixType;
    SpMat AT = A_eigen.transpose();
 
    // Reserve space for at least one value (on the diagonal). For
    // deactivated subdomains some rows and columns might end empty (in the
    // A matrix) and so no space is reserved for the Dirichlet conditions in
    // the transposed matrix. Then the coeffRef call will do costly
    // reallocations.
    AT.reserve(Eigen::VectorXi::Constant(A_eigen.rows(), 1));
 
    for (std::size_t ix = 0; ix < vec_knownX_id.size(); ix++)
    {
        SpMat::Index const row_id = vec_knownX_id[ix];
        auto const x = vec_knownX_x[ix];
 
        // b_i -= A_eigen(i,k)*val, i!=k
        // set column to zero, subtract from rhs
        for (SpMat::InnerIterator it(AT, row_id); it; ++it)
        {
            if (it.col() == row_id)
            {
                continue;
            }
 
            b_eigen[it.col()] -= it.value() * x;
            it.valueRef() = 0.0;
        }
 
        auto& c = AT.coeffRef(row_id, row_id);
        if (c != 0.0)
        {
            b_eigen[row_id] = x * c;
        }
        else
        {
            b_eigen[row_id] = x;
            c = 1.0;
        }
    }
 
    A_eigen = AT.transpose();
}

References setRowsToZeroOffDiagonal().

applyKnownSolutionIncomplete()

void anonymous_namespace{EigenTools.cpp}::applyKnownSolutionIncomplete	(	MathLib::EigenMatrix::RawMatrixType &	A_eigen,
		MathLib::EigenVector::RawVectorType &	b_eigen,
		const std::vector< MathLib::EigenMatrix::IndexType > &	vec_knownX_id,
		const std::vector< double > &	vec_knownX_x )

Definition at line 83 of file EigenTools.cpp.

{
    INFO("partial Dirichlet BC application (rhs only).");
 
    setRowsToZeroOffDiagonal(A_eigen, vec_knownX_id);
 
    Eigen::VectorXd x_known{A_eigen.rows()};
    x_known.setZero();
 
    for (auto const& [row_id, x] :
         ranges::views::zip(vec_knownX_id, vec_knownX_x))
    {
        x_known[row_id] = x;
 
        // set rhs to Dirichlet value
        auto const c = A_eigen.coeff(row_id, row_id);
        if (c != 0)
        {
            b_eigen[row_id] = x * c;
 
            // exclude diagonal (A_eigen(i,i)) from multiplication below
            // (A_eigen * x_known)
            A_eigen.coeffRef(row_id, row_id) = 0;
        }
        else
        {
            b_eigen[row_id] = x;
        }
    }
 
    b_eigen -= A_eigen * x_known;
}

References INFO(), and setRowsToZeroOffDiagonal().

setRowsToZeroOffDiagonal()

void anonymous_namespace{EigenTools.cpp}::setRowsToZeroOffDiagonal	(	MathLib::EigenMatrix::RawMatrixType &	A_eigen,
		const std::vector< MathLib::EigenMatrix::IndexType > &	row_ids )

Definition at line 12 of file EigenTools.cpp.

{
    using SpMat = MathLib::EigenMatrix::RawMatrixType;
 
    // A_eigen(k, j) = 0.
    // set row to zero
    for (auto row_id : row_ids)
    {
        for (SpMat::InnerIterator it(A_eigen, row_id); it; ++it)
        {
            if (it.col() != decltype(it.col())(row_id))
            {
                it.valueRef() = 0.0;
            }
        }
    }
}

Referenced by applyKnownSolutionComplete(), and applyKnownSolutionIncomplete().