Sync public subset from Flux (private)

include/modules/fluids/diffusion1d.h

@@ -0,0 +1,129 @@
+#pragma once
+
+#include "modules/mesh/mesh1d.h"
+#include "core/global_config.h"
+#include "utils/matrix.h"
+#include "utils/vector.h"
+
+
+
+
+namespace fluids {
+
+	template <typename T>
+	struct Diffusion1D{
+		const core::Configs<T>& cfg;
+		const mesh::Mesh1D<T>& mesh;
+		T Gamma{1};
+
+	
+
+		// Constructor
+		Diffusion1D(const core::Configs<T>& configs, const mesh::Mesh1D<T>& Mesh, T Gamma_const=T(1)): cfg(configs), mesh(Mesh), Gamma(Gamma_const) {}
+
+
+
+
+
+
+		void assemble(utils::Matrix<T>& A, utils::Vector<T>& b, utils::Vector<T>& s){
+
+			uint64_t N = mesh.center_idx + 1;
+
+			if (N < 3){
+				throw std::runtime_error("Diffusion1D: need N>=3");
+			}
+			if (A.rows() != N || A.cols() != N){
+				A = utils::Matrix<T>(N, N, T(0));
+			}
+			if (b.size() != N){
+				b = utils::Vector<T>(N, T(0));
+			}
+		
+
+			if (cfg.grid == core::GridKind::Uniform){
+				// Core of A
+				if (cfg.fd == core::FDKind::Central){
+					uniform_central_finite_diffrence_2_order(A,b,s);
+				}
+
+
+
+				// Left BC of A
+				if (cfg.left.kind == core::BCKind::Dirichlet){
+					BC_uniform_backward_finite_diffrence_2_order_Dirichlet(A,b,s);
+				}else if (cfg.left.kind == core::BCKind::Neumann){
+					BC_uniform_backward_finite_diffrence_2_order_Neumann(A,b,s);
+				}
+			}
+		}
+
+
+		void uniform_central_finite_diffrence_2_order(utils::Matrix<T>& A, utils::Vector<T>& b, utils::Vector<T>& s){
+			T xm, xc, xp;
+
+			for (uint64_t i = 1; i < mesh.center_idx; ++i){
+				xm = mesh.center(i-1);
+				xc = mesh.center(i);
+				xp = mesh.center(i+1);
+
+				A(i, i-1) = Gamma/(xc - xm);
+				A(i, i) = -((Gamma/(xp - xc)) + (Gamma/(xc - xm)));
+				A(i, i+1) = Gamma/(xp - xc);
+
+				b[i] = -s[i]*mesh.dx(i);
+			}
+		}
+
+		void BC_uniform_backward_finite_diffrence_2_order_Dirichlet(utils::Matrix<T>& A, utils::Vector<T>& b, utils::Vector<T>& s){
+			T xm;
+			T xw = mesh.vertice(0);
+			T xc = mesh.center(0);
+			T xp = mesh.center(1);
+			T xe;
+			uint64_t N = mesh.center_idx;
+
+			A(0, 0) = -((Gamma/(xp - xc)) + (Gamma/(xc - xw)));
+			A(0, 1) = Gamma/(xp - xc);
+
+			b[0] = -s[0]*mesh.dx(0) - Gamma*(cfg.left.value/(xc - xw));
+
+			xm = mesh.center(N-1);
+			xc = mesh.center(N);
+			xe = mesh.vertice(N+1);
+
+			A(N, N-1) = Gamma/(xc - xm);
+			A(N, N) = -((Gamma/(xe - xc)) + (Gamma/(xc - xm)));
+
+			b[N] = -s[N]*mesh.dx(N) - Gamma*(cfg.right.value/(xe - xc));
+			A.print();
+			b.print();
+		}
+
+		void BC_uniform_backward_finite_diffrence_2_order_Neumann(utils::Matrix<T>& A, utils::Vector<T>& b, utils::Vector<T>& s){
+			T xm;
+			T xc = mesh.center(0);
+			T xp = mesh.center(1);
+
+			uint64_t N = mesh.center_idx;
+
+			A(0, 0) = -Gamma/(xp - xc);
+			A(0, 1) = Gamma/(xp - xc);
+
+			b[0] = -s[0]*mesh.dx(0) - (Gamma*cfg.left.value);
+
+			xm = mesh.center(N-1);
+			xc = mesh.center(N);
+
+			A(N, N-1) = Gamma/(xc - xm);
+			A(N, N) = -Gamma/(xc - xm);
+
+			b[N] = -s[N]*mesh.dx(N) - Gamma*(cfg.right.value);
+
+			A.print();
+			b.print();
+		}
+
+	};
+
+} // end namespace fluids

include/modules/fluids/fluids.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include "modules/fluids/diffusion1d.h"
+
+