EigenFunctions.C

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/*---------------------------------------------------------------------------*\
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 * In real Time Highly Advanced Computational Applications for Finite Volumes
 * Copyright (C) 2017 by the ITHACA-FV authors
-------------------------------------------------------------------------------
 
License
    This file is part of ITHACA-FV
 
    ITHACA-FV is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    ITHACA-FV is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public License
    along with ITHACA-FV. If not, see <http://www.gnu.org/licenses/>.
 
\*---------------------------------------------------------------------------*/
 
#include "EigenFunctions.H"
 
// * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * * * //
 
// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
namespace EigenFunctions
{
void sortEigenvalues(Eigen::VectorXd& eigenvalues,
                     Eigen::MatrixXd& eigenvectors)
{
    labelList order;
    scalarField eigenValues(eigenvalues.size());
 
    for (label i = 0; i < eigenvalues.size(); i++)
    {
        eigenValues[i] = eigenvalues(i);
    }
 
    sortedOrder(eigenValues, order);
    scalarField eigenValues2(eigenValues);
 
    for (label i = 0; i < order.size(); i++)
    {
        eigenvalues(i) = eigenValues[order[order.size() - i - 1]];
    }
 
    Eigen::MatrixXd eigenvectors2 = eigenvectors;
 
    for (label i = 0; i < eigenvalues.size(); i++)
    {
        for (label k = 0; k < eigenvalues.size(); k++)
        {
            eigenvectors2(i, k) = eigenvectors(k, order[order.size() - i - 1]);
        }
    }
 
    eigenvectors = eigenvectors2;
}
 
 
Eigen::VectorXd ExpSpaced(double first, double last, int n)
{
    Eigen::VectorXd vector(n);
    double m = (double) 1 / (n * 1.0 - 1);
    double quotient = std::pow(last / first, m);
    vector(0) = first;
 
    for (int i = 1; i < n; i++)
    {
        vector(i) = vector(i - 1) * quotient;
    }
 
    return vector;
}
 
template <typename T>
Eigen::Matrix<T, Eigen::Dynamic, Eigen::Dynamic>
vectorTensorProduct(const Eigen::Matrix<T, Eigen::Dynamic, 1>&
                    g,
                    const Eigen::Tensor<T, 3 >& c,
                    const Eigen::Matrix<T, Eigen::Dynamic, 1>& a)
{
    int prodDim = c.dimension(0);
    Eigen::Matrix<T, Eigen::Dynamic, Eigen::Dynamic> prod;
    prod.resize(prodDim, 1);
 
    for (int i = 0; i < prodDim; i++)
    {
        prod(i, 0) = g.transpose() *
                     SliceFromTensor(c, 0, i) * a;
    }
 
    return prod;
}
 
template Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic>
vectorTensorProduct<>(
    const Eigen::Matrix<double, Eigen::Dynamic, 1>& g,
    const Eigen::Tensor<double, 3 >& c,
    const Eigen::Matrix<double, Eigen::Dynamic, 1>& a);
 
template Eigen::Matrix<int, Eigen::Dynamic, Eigen::Dynamic>
vectorTensorProduct(
    const Eigen::Matrix<int, Eigen::Dynamic, 1>& g, const Eigen::Tensor<int, 3 >& c,
    const Eigen::Matrix<int, Eigen::Dynamic, 1>& a);
 
template Eigen::Matrix<float, Eigen::Dynamic, Eigen::Dynamic>
vectorTensorProduct(
    const Eigen::Matrix<float, Eigen::Dynamic, 1>& g,
    const Eigen::Tensor<float, 3 >& c,
    const Eigen::Matrix<float, Eigen::Dynamic, 1>& a);
}