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Sync public subset from Flux (private)

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Gitea CI
2025-10-06 20:14:13 +00:00
parent 272e77c536
commit b2d00af0e1
390 changed files with 152131 additions and 0 deletions
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58
include/modules/finitedifference1d.h Normal file
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#pragma once
#include "modules/grid1d.h"
namespace fd1d {
// -----------------------------------------------------------------------------
// Second derivative (u_xx) at interior cell i, central difference
// Works on NON-uniform grids
// On uniform: (u[i-1] - 2 u[i] + u[i+1]) / dx^2
// -----------------------------------------------------------------------------
template <typename T>
void inplace_Build_CentralDerivative_Matrix(const fvm::Grid1D<T>& g, utils::Matrix<T>& A, utils::Vector<T>& b, const utils::Vector<T>& s, const T& c){
for (uint64_t i = 1; i < g.center_idx; ++i){
A(i,i-1) = -(c/(g.centers[i] - g.centers[i-1]));
A(i,i) = -((c/(g.centers[i+1] - g.centers[i])) + (c/(g.centers[i] - g.centers[i-1])));
A(i,i+1) = -(c/(g.centers[i+1] - g.centers[i]));
b[i] = -s[i]*(g.vertices[i+1] - g.vertices[i]);
}
}
template <typename T>
utils::Matrix<T> Build_CentralDerivative_Matrix(const fvm::Grid1D<T>& g, utils::Vector<T>& b, const utils::Vector<T>& s, const T& c){
utils::Matrix<T> A(g.center_idx+1, g.center_idx+1, T{0});
inplace_Build_CentralDerivative_Matrix(g, A, b, s, c);
return A;
}
template <typename T>
void inplace_BC_Dirichlet(const fvm::Grid1D<T>& g, utils::Matrix<T>& A, utils::Vector<T>& b, const utils::Vector<T>& s, const T& c){
A(0,0) = -((c/(g.centers[1] - g.centers[0])) + (c/(g.centers[0] - g.vertices[0])));
A(0,1) = c/(g.centers[1] - g.centers[0]);
A(g.center_idx, g.center_idx-1) = c/(g.centers[g.center_idx]-g.centers[g.center_idx-1]);
A(g.center_idx, g.center_idx) = -((c/(g.vertices[g.vertices_idx] - g.centers[g.center_idx])) + (c/(g.centers[g.center_idx] - g.centers[g.center_idx-1])));
}
template <typename T>
void inplace_BC_Neumann(const fvm::Grid1D<T>& g, utils::Matrix<T>& A, const T& c){
A(0,0) = -c/(g.centers[1]-g.centers[0]);
A(0,1) = c/(g.centers[1]-g.centers[0]);
A(g.center_idx, g.center_idx-1) = c/(g.centers[g.center_idx]-g.centers[g.center_idx-1]);
A(g.center_idx, g.center_idx) = -c/(g.centers[g.center_idx]-g.centers[g.center_idx-1]);
}
}