<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">Velocity rescaling is a quite well established technique (please refer to the thousands of paper discussing merits and drawbacks of it).. <DIV>if you want the kinetic energy of a set of variable to be equal to a certain value within a tol (with velocity rescalinf) this is the correct equation to use:<DIV><BR class="khtml-block-placeholder"></DIV><DIV><DIV><BLOCKQUOTE type="cite"><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "> IF(ABS(ekin_w-meta_env%ekin_s)> tol_ekin)THEN<BR><BR></SPAN></BLOCKQUOTE><DIV><BR class="khtml-block-placeholder"></DIV>With this one :<BR><BLOCKQUOTE type="cite"><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; ">should be changed into (the following is my own change, not from CVS)<BR> IF((-ekin_w+meta_env%ekin_s)> tol_ekin)THEN<BR><BR></SPAN></BLOCKQUOTE><DIV><BR class="khtml-block-placeholder"></DIV>the temperature of your collective variable could be much lower than the one at which you may want to sample the free energy..</DIV><DIV>No doubt the temperature of the collective variables should be equal to the temperature at which you want to compute the free energy.</DIV><DIV><BR><BLOCKQUOTE type="cite"><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; ">As I said yesterday, my understanding is that only the high velocity should be avoided. If the low velocity is also scaled to high velocity, variable will always decreas or increase linearly.<SPAN class="Apple-converted-space"> </SPAN><BR></SPAN></BLOCKQUOTE></DIV><BR></DIV><DIV>Teo</DIV><DIV><BR class="khtml-block-placeholder"></DIV></DIV></BODY></HTML>