<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#FFFFFF">
On 22/11/2011 7:27 PM, xuji wrote:
<blockquote cite="mid:201111221627587713388@home.ipe.ac.cn"
type="cite">
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
<meta name="GENERATOR" content="MSHTML 8.00.7600.16385">
<style>@font-face {
font-family: 宋体;
}
@font-face {
font-family: Verdana;
}
@font-face {
font-family: @宋体;
}
@page Section1 {size: 595.3pt 841.9pt; margin: 72.0pt 90.0pt 72.0pt 90.0pt; layout-grid: 15.6pt; }
P.MsoNormal {
TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Times New Roman"; FONT-SIZE: 10.5pt
}
LI.MsoNormal {
TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Times New Roman"; FONT-SIZE: 10.5pt
}
DIV.MsoNormal {
TEXT-JUSTIFY: inter-ideograph; TEXT-ALIGN: justify; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Times New Roman"; FONT-SIZE: 10.5pt
}
A:link {
COLOR: blue; TEXT-DECORATION: underline
}
SPAN.MsoHyperlink {
COLOR: blue; TEXT-DECORATION: underline
}
A:visited {
COLOR: purple; TEXT-DECORATION: underline
}
SPAN.MsoHyperlinkFollowed {
COLOR: purple; TEXT-DECORATION: underline
}
SPAN.EmailStyle17 {
FONT-STYLE: normal; FONT-FAMILY: Verdana; COLOR: windowtext; FONT-WEIGHT: normal; TEXT-DECORATION: none; mso-style-type: personal-compose
}
DIV.Section1 {
page: Section1
}
UNKNOWN {
FONT-SIZE: 10pt
}
BLOCKQUOTE {
MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px; MARGIN-LEFT: 2em
}
OL {
MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px
}
UL {
MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px
}
</style>
<div><font size="2" color="#000080" face="Verdana">Hi all-gmxers</font></div>
<div> </div>
<div><font color="#000080">The force equations of old virtual site
type 4fd were shown in GROMACS manual.</font></div>
<div><font color="#000080">But the ones of corresponding new type
4fdn are not shown in new GROMACS manual.</font></div>
<div><font color="#000080">Can someone do me a favor to give the
force equations?</font></div>
</blockquote>
<br>
You will have seen that the manual also says:<br>
<br>
The force<br>
on particles i, j, k and l due to the force on the virtual site are
computed through chain rule<br>
derivatives of the construction expression. This is exact and
conserves energy, but it does<br>
lead to relatively lengthy expressions that we do not include here
(over 200 floating-point<br>
operations). The interested reader can look at the source code in
vsite.c.<br>
<br>
Perhaps you should try this.<br>
<br>
Mark<br>
</body>
</html>