+ /* energy averages & fluctuations */
+ double k_sum; /* sum of kinetic energy */
+ double v_sum; /* sum of potential energy */
+ double k_mean; /* average of kinetic energy */
+ double v_mean; /* average of potential energy */
+ double k2_sum; /* sum of kinetic energy squared */
+ double v2_sum; /* sum of potential energy squared */
+ double k2_mean; /* average of kinetic energy squared */
+ double v2_mean; /* average of potential energy squared */
+ double dk2_mean; /* mean square kinetic energy fluctuations */
+ double dv2_mean; /* mean square potential energy fluctuations */
+
+ /* response functions */
+ double c_v_nve; /* constant volume heat capacity (nve) */
+ double c_v_nvt; /* constant volume heat capacity (nvt) */
+