mirror of
https://git.gfz-potsdam.de/naaice/tug.git
synced 2025-12-14 01:48:23 +01:00
125 lines
3.3 KiB
C++
125 lines
3.3 KiB
C++
#include "BTCSDiffusion.hpp"
|
|
|
|
#include <Eigen/SparseCholesky>
|
|
#include <Eigen/SparseLU>
|
|
#include <Eigen/SparseQR>
|
|
#include <Eigen/src/Core/Matrix.h>
|
|
#include <Eigen/src/Core/util/Constants.h>
|
|
#include <Eigen/src/OrderingMethods/Ordering.h>
|
|
#include <Eigen/src/SparseCholesky/SimplicialCholesky.h>
|
|
#include <Eigen/src/SparseCore/SparseMap.h>
|
|
#include <Eigen/src/SparseCore/SparseMatrix.h>
|
|
#include <Eigen/src/SparseCore/SparseMatrixBase.h>
|
|
#include <Eigen/src/SparseLU/SparseLU.h>
|
|
#include <Eigen/src/SparseQR/SparseQR.h>
|
|
|
|
#include <algorithm>
|
|
#include <iomanip>
|
|
#include <iostream>
|
|
#include <tuple>
|
|
|
|
const int BTCSDiffusion::BC_NEUMANN = 0;
|
|
const int BTCSDiffusion::BC_DIRICHLET = 1;
|
|
|
|
BTCSDiffusion::BTCSDiffusion(int x) : dim_x(x) {
|
|
this->grid_dim = 1;
|
|
|
|
// per default use Neumann condition with gradient of 0 at the end of the grid
|
|
this->bc.resize(2, std::tuple<int, double>(0,0.));
|
|
}
|
|
BTCSDiffusion::BTCSDiffusion(int x, int y) : dim_x(x), dim_y(y) {
|
|
|
|
// this->grid_dim = 2;
|
|
|
|
// this->bc.reserve(x * 2 + y * 2);
|
|
// // per default use Neumann condition with gradient of 0 at the end of the grid
|
|
// std::fill(this->bc.begin(), this->bc.end(), -1);
|
|
}
|
|
BTCSDiffusion::BTCSDiffusion(int x, int y, int z)
|
|
: dim_x(x), dim_y(y), dim_z(z) {
|
|
|
|
// this->grid_dim = 3;
|
|
// TODO: reserve memory for boundary conditions
|
|
}
|
|
|
|
void BTCSDiffusion::simulate(std::vector<double> &c, std::vector<double> &alpha,
|
|
double timestep) {
|
|
// calculate dx
|
|
double dx = 1. / (this->dim_x - 1);
|
|
|
|
// calculate size needed for A matrix and b,x vectors
|
|
int size = this->dim_x + 2;
|
|
|
|
Eigen::VectorXd b = Eigen::VectorXd::Constant(size, 0);
|
|
Eigen::VectorXd x_out(size);
|
|
|
|
/*
|
|
* Initalization of matrix A
|
|
* This is done by triplets. See:
|
|
* https://eigen.tuxfamily.org/dox/group__TutorialSparse.html
|
|
*/
|
|
|
|
std::vector<T> tripletList;
|
|
tripletList.reserve(c.size() * 3 + bc.size());
|
|
|
|
int A_line = 0;
|
|
|
|
// For all concentrations create one row in matrix A
|
|
for (int i = 1; i < this->dim_x + 1; i++) {
|
|
double sx = (alpha[i - 1] * timestep) / (dx * dx);
|
|
|
|
tripletList.push_back(T(A_line, i, (-1. - 2. * sx)));
|
|
|
|
tripletList.push_back(T(A_line, i - 1, sx));
|
|
tripletList.push_back(T(A_line, i + 1, sx));
|
|
|
|
b[A_line] = -c[i - 1];
|
|
A_line++;
|
|
}
|
|
|
|
// append left and right boundary conditions/ghost zones
|
|
tripletList.push_back(T(A_line, 0, 1));
|
|
|
|
// if value is -1 apply Neumann condition with given gradient
|
|
// TODO: set specific gradient
|
|
if (bc[0] == -1)
|
|
b[A_line] = c[0];
|
|
// else apply given Dirichlet condition
|
|
else
|
|
b[A_line] = this->bc[0];
|
|
|
|
A_line++;
|
|
tripletList.push_back(T(A_line, size - 1, 1));
|
|
// b[A_line] = bc[1];
|
|
if (bc[1] == -1)
|
|
b[A_line] = c[c.size() - 1];
|
|
else
|
|
b[A_line] = this->bc[1];
|
|
|
|
/*
|
|
* Begin to solve the equation system
|
|
*
|
|
* At this point there is some debugging output in the code.
|
|
* TODO: remove output
|
|
*/
|
|
|
|
Eigen::SparseMatrix<double> A(size, size);
|
|
A.setFromTriplets(tripletList.begin(), tripletList.end());
|
|
|
|
Eigen::SparseLU<Eigen::SparseMatrix<double>, Eigen::COLAMDOrdering<int>>
|
|
solver;
|
|
solver.analyzePattern(A);
|
|
|
|
solver.factorize(A);
|
|
|
|
std::cout << solver.lastErrorMessage() << std::endl;
|
|
|
|
x_out = solver.solve(b);
|
|
|
|
std::cout << std::setprecision(10) << x_out << std::endl << std::endl;
|
|
|
|
for (int i = 0; i < c.size(); i++) {
|
|
c[i] = x_out[i + 1];
|
|
}
|
|
}
|