Add C++ Energy class

Author: rpep

c_energy.cpp

@@ -0,0 +1,29 @@
+#include<cmath>
+
+class Energy {
+public:
+    bool set_up;
+    Energy();
+    int nx, ny, nz, n;
+    double dx, dy, dz;
+    double unit_length;
+    double *spin;
+    double *Ms;
+    double *Ms_inv;
+    double *field;
+    double *energy;
+    double *coordinates;
+    int *ngbs;
+    virtual void compute_field(double t) = 0;
+    double compute_energy();
+    void setup(int nx, int ny, int nz, double dx, double dy, double dz, double unit_length, double *spin, double *Ms, double *Ms_inv);
+};
+
+class Exchange : public Energy {
+public:
+    Exchange(double *A) : A(A) {
+        set_up = false;
+    }
+    double *A;
+    void compute_field(double t);
+};