metadynamic

[lml... at gmail.com]

Hi,
I think that the part of controlling temperature ss0 (metadynamics.F)
may be not right.  The aim to control temperture is to aviod high
speed of ss0.  Using current setting, it will not get the right
results because ss0 can not fluctuate, but it only increases.

   IF(ABS(ekin_w-meta_env%ekin_s)> tol_ekin)THEN
 !!!          IF((-ekin_w+meta_env%ekin_s)> tol_ekin)THEN

I hope that my understanding is right. If I am wrong, please let me
know.

Best Regards,
Limin