+ double t_ref; /* reference temperature */
+ double t; /* actual temperature */
+
+ double p_ref; /* reference pressure */
+ double p; /* actual pressure */
+
+ /* pressure and temperature control (velocity/volume scaling) */
+ unsigned char pt_scale; /* type of p and t scaling */
+ double t_tc; /* t berendsen control time constant */
+ double p_tc; /* p berendsen control time constant */