<br><br><div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br><br>---------- Пересланное письмо ----------
<br>From: David van der Spoel <<a href="mailto:spoel@xray.bmc.uu.se">spoel@xray.bmc.uu.se</a>><br>To: Discussion list for GROMACS users <<a href="mailto:gmx-users@gromacs.org">gmx-users@gromacs.org</a>><br>Date: Fri, 26 Jan 2007 10:02:01 +0100
<br>Subject: Re: [gmx-users] g_gyrate<br>Dmitriy Golubobsky wrote:<br>> Dear Gurus,<br>> I've got question on Radius of gyrtion calculation.<br>> my system consists of 1 polymer and a solvent.<br>> I did MD and decide to calculate Rg for this system
<br>> I made index group consisting my residues<br>> g_gyrate -f xtc_file -s tpr_file -n ndx_file -p -o xvg_output<br>> ok. I've got the output file with 4 colums: time Rg Rx Ry Rz<br>> I use -p option to get components in principal axes, because I' d like
<br>> to calculate form-factors for my system.<br>><br>> as I undersand Rg = sqrt ( sum_{i}^{N} r_i*m_i)/M)<br>> ok. then fx=Rx/Rg^2, fy=Ry/Rg^2, fz=Rz/Rg^2<br>> and I wish to get fx+fy+fz=1 but it is not so.
<br>> where I'm mistaken?<br>> How does components Rxyz in principal axes are calculated?<br>> I'm using gromacs 3.3.1<br>> Thanks a lot.<br>Rg = sqrt ( sum_{i}^{N} (r_i^2)*m_i)/M)<br><br>--<br>David.<br>
<br></blockquote></div>Dear David,<br>I understand this, thus for the <br>Rx=Rg = sqrt ( sum_{i}^{N} (x_i^2)*m_i)/M)<br><br>and we have to get Rx^2+Ry^2+Rz^2=Rg^2<br>but we didn't get this.<br>