git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@15571 f3b2605a-c512-4ea7-a41b-209d697bcdaa
This commit is contained in:
@ -128,9 +128,9 @@
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<span id="index-0"></span><h1>comm_modify command</h1>
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<div class="section" id="syntax">
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<h2>Syntax</h2>
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<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">comm_modify</span> <span class="n">keyword</span> <span class="n">value</span> <span class="o">...</span>
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</pre></div>
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</div>
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<pre class="literal-block">
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comm_modify keyword value ...
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</pre>
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<ul class="simple">
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<li>zero or more keyword/value pairs may be appended</li>
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<li>keyword = <em>mode</em> or <em>cutoff</em> or <em>cutoff/multi</em> or <em>group</em> or <em>vel</em></li>
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@ -147,14 +147,14 @@
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</div>
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<div class="section" id="examples">
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<h2>Examples</h2>
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<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">comm_modify</span> <span class="n">mode</span> <span class="n">multi</span>
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<span class="n">comm_modify</span> <span class="n">mode</span> <span class="n">multi</span> <span class="n">group</span> <span class="n">solvent</span>
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<span class="n">comm_modift</span> <span class="n">mode</span> <span class="n">multi</span> <span class="n">cutoff</span><span class="o">/</span><span class="n">multi</span> <span class="mi">1</span> <span class="mf">10.0</span> <span class="n">cutoff</span><span class="o">/</span><span class="n">multi</span> <span class="mi">2</span><span class="o">*</span><span class="mi">4</span> <span class="mf">15.0</span>
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<span class="n">comm_modify</span> <span class="n">vel</span> <span class="n">yes</span>
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<span class="n">comm_modify</span> <span class="n">mode</span> <span class="n">single</span> <span class="n">cutoff</span> <span class="mf">5.0</span> <span class="n">vel</span> <span class="n">yes</span>
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<span class="n">comm_modify</span> <span class="n">cutoff</span><span class="o">/</span><span class="n">multi</span> <span class="o">*</span> <span class="mf">0.0</span>
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</pre></div>
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</div>
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<pre class="literal-block">
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comm_modify mode multi
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comm_modify mode multi group solvent
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comm_modift mode multi cutoff/multi 1 10.0 cutoff/multi 2*4 15.0
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comm_modify vel yes
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comm_modify mode single cutoff 5.0 vel yes
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comm_modify cutoff/multi * 0.0
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</pre>
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</div>
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<div class="section" id="description">
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<h2>Description</h2>
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@ -135,18 +135,25 @@
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<li>ID, group-ID are documented in <a class="reference internal" href="compute.html"><span class="doc">compute</span></a> command</li>
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<li>bond/local = style name of this compute command</li>
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<li>one or more values may be appended</li>
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<li>value = <em>dist</em> or <em>eng</em> or <em>force</em></li>
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<li>value = <em>dist</em> or <em>engpot</em> or <em>force</em> or <em>engvib</em> or <em>engrot</em> or <em>engtrans</em> or <em>omega</em> or <em>velvib</em></li>
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</ul>
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<pre class="literal-block">
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<em>dist</em> = bond distance
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<em>eng</em> = bond energy
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<em>engpot</em> = bond potential energy
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<em>force</em> = bond force
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</pre>
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<pre class="literal-block">
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<em>engvib</em> = bond kinetic energy of vibration
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<em>engrot</em> = bond kinetic energy of rotation
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<em>engtrans</em> = bond kinetic energy of translation
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<em>omega</em> = magnitude of bond angular velocity
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<em>velvib</em> = vibrational velocity along the bond length
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</pre>
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</div>
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<div class="section" id="examples">
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<h2>Examples</h2>
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<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">compute</span> <span class="mi">1</span> <span class="nb">all</span> <span class="n">bond</span><span class="o">/</span><span class="n">local</span> <span class="n">eng</span>
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<span class="n">compute</span> <span class="mi">1</span> <span class="nb">all</span> <span class="n">bond</span><span class="o">/</span><span class="n">local</span> <span class="n">dist</span> <span class="n">eng</span> <span class="n">force</span>
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<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">compute</span> <span class="mi">1</span> <span class="nb">all</span> <span class="n">bond</span><span class="o">/</span><span class="n">local</span> <span class="n">engpot</span>
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<span class="n">compute</span> <span class="mi">1</span> <span class="nb">all</span> <span class="n">bond</span><span class="o">/</span><span class="n">local</span> <span class="n">dist</span> <span class="n">engpot</span> <span class="n">force</span>
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</pre></div>
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</div>
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</div>
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@ -154,12 +161,42 @@
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<h2>Description</h2>
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<p>Define a computation that calculates properties of individual bond
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interactions. The number of datums generated, aggregated across all
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processors, equals the number of bonds in the system, modified
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by the group parameter as explained below.</p>
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<p>The value <em>dist</em> is the length of the bond.</p>
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<p>The value <em>eng</em> is the interaction energy for the bond.</p>
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<p>The value <em>force</em> is the force acting between the pair of atoms in the
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processors, equals the number of bonds in the system, modified by the
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group parameter as explained below.</p>
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<p>The value <em>dist</em> is the current length of the bond.</p>
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<p>The value <em>engpot</em> is the potential energy for the bond,
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based on the current separation of the pair of atoms in the bond.</p>
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<p>The value <em>force</em> is the magnitude of the force acting between the
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pair of atoms in the bond.</p>
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<p>The remaining properties are all computed for motion of the two atoms
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relative to the center of mass (COM) velocity of the 2 atoms in the
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bond.</p>
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<p>The value <em>engvib</em> is the vibrational kinetic energy of the two atoms
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in the bond, which is simply 1/2 m1 v1^2 + 1/2 m1 v2^2, where v1 and
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v2 are the magnitude of the velocity of the 2 atoms along the bond
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direction, after the COM velocity has been subtracted from each.</p>
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<p>The value <em>engrot</em> is the rotationsl kinetic energy of the two atoms
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in the bond, which is simply 1/2 m1 v1^2 + 1/2 m1 v2^2, where v1 and
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v2 are the magnitude of the velocity of the 2 atoms perpendicular to
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the bond direction, after the COM velocity has been subtracted from
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each.</p>
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<p>The value <em>engtrans</em> is the translational kinetic energy associated
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with the motion of the COM of the system itself, namely 1/2 (m1+m2)
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Vcm^2 where Vcm = magnitude of the velocity of the COM.</p>
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<p>Note that these 3 kinetic energy terms are simply a partitioning of
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the summed kinetic energy of the 2 atoms themselves. I.e. total KE =
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1/2 m1 v1^2 + 1/2 m2 v3^2 = engvib + engrot + engtrans, where v1,v2
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are the magnitude of the velocities of the 2 atoms, without any
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adjustment for the COM velocity.</p>
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<p>The value <em>omega</em> is the magnitude of the angular velocity of the
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two atoms around their COM position.</p>
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<p>The value <em>velvib</em> is the magnitude of the relative velocity of the
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two atoms in the bond towards each other. A negative value means the
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2 atoms are moving toward each other; a positive value means they are
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moving apart.</p>
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<p>Note that all these properties are computed for the pair of atoms in a
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bond, whether the 2 atoms represent a simple diatomic molecule, or are
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part of some larger molecule.</p>
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<p>The local data stored by this command is generated by looping over all
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the atoms owned on a processor and their bonds. A bond will only be
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included if both atoms in the bond are in the specified compute group.
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@ -179,8 +216,8 @@ command in a consistent way.</p>
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<p>Here is an example of how to do this:</p>
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<pre class="literal-block">
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compute 1 all property/local btype batom1 batom2
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compute 2 all bond/local dist eng
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dump 1 all local 1000 tmp.dump index c_1[1] c_1[2] c_1[3] c_2[1] c_2[2]
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compute 2 all bond/local dist engpot
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dump 1 all local 1000 tmp.dump index c_1[*] c_2[*]
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</pre>
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<p><strong>Output info:</strong></p>
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<p>This compute calculates a local vector or local array depending on the
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@ -191,9 +228,12 @@ local array is produced where the number of columns = the number of
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keywords. The vector or array can be accessed by any command that
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uses local values from a compute as input. See <a class="reference internal" href="Section_howto.html#howto-15"><span class="std std-ref">this section</span></a> for an overview of LAMMPS output
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options.</p>
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<p>The output for <em>dist</em> will be in distance <a class="reference internal" href="units.html"><span class="doc">units</span></a>. The
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output for <em>eng</em> will be in energy <a class="reference internal" href="units.html"><span class="doc">units</span></a>. The output for
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<em>force</em> will be in force <a class="reference internal" href="units.html"><span class="doc">units</span></a>.</p>
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<p>The output for <em>dist</em> will be in distance <a class="reference internal" href="units.html"><span class="doc">units</span></a>. The
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output for <em>velvib</em> will be in velocity <a class="reference internal" href="units.html"><span class="doc">units</span></a>. The output
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for <em>omega</em> will be in velocity/distance <a class="reference internal" href="units.html"><span class="doc">units</span></a>. The
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output for <em>engtrans</em>, <em>engvib</em>, <em>engrot</em>, and <em>engpot</em> will be in
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energy <a class="reference internal" href="units.html"><span class="doc">units</span></a>. The output for <em>force</em> will be in force
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<a class="reference internal" href="units.html"><span class="doc">units</span></a>.</p>
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</div>
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<div class="section" id="restrictions">
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<h2>Restrictions</h2>
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@ -344,7 +344,7 @@
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</dt>
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<dt><a href="comm_modify.html#index-0">comm_modify</a>
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<dt><a href="comm_modify.html#index-0">comm\_modify</a>
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</dt>
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@ -15,31 +15,74 @@ compute ID group-ID bond/local value1 value2 ... :pre
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ID, group-ID are documented in "compute"_compute.html command :ulb,l
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bond/local = style name of this compute command :l
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one or more values may be appended :l
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value = {dist} or {eng} or {force} :l
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value = {dist} or {engpot} or {force} or {engvib} or {engrot} or {engtrans} or {omega} or {velvib} :l
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{dist} = bond distance
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{eng} = bond energy
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{engpot} = bond potential energy
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{force} = bond force :pre
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{engvib} = bond kinetic energy of vibration
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{engrot} = bond kinetic energy of rotation
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{engtrans} = bond kinetic energy of translation
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{omega} = magnitude of bond angular velocity
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{velvib} = vibrational velocity along the bond length :pre
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:ule
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[Examples:]
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compute 1 all bond/local eng
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compute 1 all bond/local dist eng force :pre
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compute 1 all bond/local engpot
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compute 1 all bond/local dist engpot force :pre
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[Description:]
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Define a computation that calculates properties of individual bond
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interactions. The number of datums generated, aggregated across all
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processors, equals the number of bonds in the system, modified
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by the group parameter as explained below.
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processors, equals the number of bonds in the system, modified by the
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group parameter as explained below.
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The value {dist} is the length of the bond.
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The value {dist} is the current length of the bond.
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The value {eng} is the interaction energy for the bond.
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The value {engpot} is the potential energy for the bond,
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based on the current separation of the pair of atoms in the bond.
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The value {force} is the force acting between the pair of atoms in the
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The value {force} is the magnitude of the force acting between the
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pair of atoms in the bond.
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The remaining properties are all computed for motion of the two atoms
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relative to the center of mass (COM) velocity of the 2 atoms in the
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bond.
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The value {engvib} is the vibrational kinetic energy of the two atoms
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in the bond, which is simply 1/2 m1 v1^2 + 1/2 m1 v2^2, where v1 and
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v2 are the magnitude of the velocity of the 2 atoms along the bond
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direction, after the COM velocity has been subtracted from each.
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The value {engrot} is the rotationsl kinetic energy of the two atoms
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in the bond, which is simply 1/2 m1 v1^2 + 1/2 m1 v2^2, where v1 and
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v2 are the magnitude of the velocity of the 2 atoms perpendicular to
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the bond direction, after the COM velocity has been subtracted from
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each.
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The value {engtrans} is the translational kinetic energy associated
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with the motion of the COM of the system itself, namely 1/2 (m1+m2)
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Vcm^2 where Vcm = magnitude of the velocity of the COM.
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Note that these 3 kinetic energy terms are simply a partitioning of
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the summed kinetic energy of the 2 atoms themselves. I.e. total KE =
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1/2 m1 v1^2 + 1/2 m2 v3^2 = engvib + engrot + engtrans, where v1,v2
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are the magnitude of the velocities of the 2 atoms, without any
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adjustment for the COM velocity.
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The value {omega} is the magnitude of the angular velocity of the
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two atoms around their COM position.
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The value {velvib} is the magnitude of the relative velocity of the
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two atoms in the bond towards each other. A negative value means the
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2 atoms are moving toward each other; a positive value means they are
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moving apart.
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Note that all these properties are computed for the pair of atoms in a
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bond, whether the 2 atoms represent a simple diatomic molecule, or are
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part of some larger molecule.
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The local data stored by this command is generated by looping over all
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the atoms owned on a processor and their bonds. A bond will only be
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included if both atoms in the bond are in the specified compute group.
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@ -62,8 +105,8 @@ command in a consistent way.
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Here is an example of how to do this:
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compute 1 all property/local btype batom1 batom2
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compute 2 all bond/local dist eng
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dump 1 all local 1000 tmp.dump index c_1\[1\] c_1\[2\] c_1\[3\] c_2\[1\] c_2\[2\] :pre
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compute 2 all bond/local dist engpot
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dump 1 all local 1000 tmp.dump index c_1\[*\] c_2\[*\] :pre
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[Output info:]
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@ -77,9 +120,12 @@ uses local values from a compute as input. See "this
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section"_Section_howto.html#howto_15 for an overview of LAMMPS output
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options.
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The output for {dist} will be in distance "units"_units.html. The
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output for {eng} will be in energy "units"_units.html. The output for
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{force} will be in force "units"_units.html.
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The output for {dist} will be in distance "units"_units.html. The
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output for {velvib} will be in velocity "units"_units.html. The output
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for {omega} will be in velocity/distance "units"_units.html. The
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output for {engtrans}, {engvib}, {engrot}, and {engpot} will be in
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energy "units"_units.html. The output for {force} will be in force
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"units"_units.html.
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[Restrictions:] none
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Reference in New Issue
Block a user