+}
+
+int energy_fluctuation_calc(t_moldyn *moldyn) {
+
+ if(moldyn->total_steps<moldyn->mean_skip)
+ return 0;
+
+ /* assume up to date energies */
+
+ /* kinetic energy */
+ moldyn->k_sum+=moldyn->ekin;
+ moldyn->k2_sum+=(moldyn->ekin*moldyn->ekin);
+ moldyn->k_mean=moldyn->k_sum/(moldyn->total_steps+1-moldyn->mean_skip);
+ moldyn->k2_mean=moldyn->k2_sum/
+ (moldyn->total_steps+1-moldyn->mean_skip);
+ moldyn->dk2_mean=moldyn->k2_mean-(moldyn->k_mean*moldyn->k_mean);
+
+ /* potential energy */
+ moldyn->v_sum+=moldyn->energy;
+ moldyn->v2_sum+=(moldyn->energy*moldyn->energy);
+ moldyn->v_mean=moldyn->v_sum/(moldyn->total_steps+1-moldyn->mean_skip);
+ moldyn->v2_mean=moldyn->v2_sum/
+ (moldyn->total_steps+1-moldyn->mean_skip);
+ moldyn->dv2_mean=moldyn->v2_mean-(moldyn->v_mean*moldyn->v_mean);
+
+ return 0;
+}
+
+int get_heat_capacity(t_moldyn *moldyn) {
+
+ double temp2,ighc;
+
+ /* averages needed for heat capacity calc */
+ if(moldyn->total_steps<moldyn->mean_skip)
+ return 0;
+
+ /* (temperature average)^2 */
+ temp2=moldyn->mean_t*moldyn->mean_t;
+ printf("[moldyn] specific heat capacity for T=%f K [J/(kg K)]\n",
+ moldyn->mean_t);
+
+ /* ideal gas contribution */
+ ighc=3.0*moldyn->count*K_BOLTZMANN/2.0;
+ printf(" ideal gas contribution: %f\n",
+ ighc/moldyn->mass*KILOGRAM/JOULE);
+
+ /* specific heat for nvt ensemble */
+ moldyn->c_v_nvt=moldyn->dv2_mean/(K_BOLTZMANN*temp2)+ighc;
+ moldyn->c_v_nvt/=moldyn->mass;
+
+ /* specific heat for nve ensemble */
+ moldyn->c_v_nve=ighc/(1.0-(moldyn->dv2_mean/(ighc*K_BOLTZMANN*temp2)));
+ moldyn->c_v_nve/=moldyn->mass;
+
+ printf(" NVE: %f\n",moldyn->c_v_nve*KILOGRAM/JOULE);
+ printf(" NVT: %f\n",moldyn->c_v_nvt*KILOGRAM/JOULE);
+printf(" --> <dV2> sim: %f experimental: %f\n",moldyn->dv2_mean,1.5*moldyn->count*K_B2*moldyn->mean_t*moldyn->mean_t*(1.0-1.5*moldyn->count*K_BOLTZMANN/(700*moldyn->mass*JOULE/KILOGRAM)));
+
+ return 0;
+}