Sync public subset from Flux (private)

include/modules/field1d.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include "utils/vector.h"
+#include "modules/grid1d.h"
+
+
+namespace fvm {
+
+	template <typename T>
+
+	struct Field1D{
+
+	    const Grid1D* grid = nullptr;   // not owning
+	    utils::Vector<T> u; 			// size = grid->N
+		                          
+		Field1D() = default;
+
+		explicit Field1D(const Grid1D& g, double init = 0.0) : grid(&g), u(g.N){
+			
+		}
+
+		void generate_vertices(){
+			vertices.resize(N_vertices);
+			vertices[0] = centers[0] - ((centers[1] - centers[0])*0.5);	
+			vertices[N_vertices-1] = centers[N_centers-1] + ((centers[N_centers-1] - centers[N_centers-2])*0.5);
+			for (uint64_t i = 1; i < N_centers; ++i){
+				vertices[i] = (centers[i-1] + centers[i])*0.5;
+			}
+		}
+
+		T dx(uint64_t i) const { check(i); return vertices(i+1) - vertices(i); }
+		T center(uint64_t i) const { check(i); return centers(i); }
+private:
+	    void check(uint64_t i) const {
+	        if (i >= N_centers) throw std::runtime_error("Grid1D: cell index out of range");
+	    }
+	};
+
+
+}