<HTML> <CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A> </CENTER> <HR> <H3>compute_modify command </H3> <P><B>Syntax:</B> </P> <PRE>compute_modify compute-ID keyword value ... </PRE> <UL><LI>compute-ID = ID of the compute to modify <LI>one or more keyword/value pairs may be listed <LI>keyword = <I>extra</I> or <I>dynamic</I> <PRE> <I>extra</I> value = N N = # of extra degrees of freedom to subtract <I>dynamic</I> value = <I>yes</I> or <I>no</I> yes/no = do or do not recompute the number of atoms contributing to the temperature </PRE> </UL> <P><B>Examples:</B> </P> <PRE>compute_modify myTemp extra 0 compute_modify newtemp dynamic yes extra 600 </PRE> <P><B>Description:</B> </P> <P>Modify one or more parameters of a previously defined compute. Not all compute styles support all parameters. </P> <P>The <I>extra</I> keyword refers to how many degrees-of-freedom are subtracted (typically from 3N) as a normalizing factor in a temperature computation. Only computes that compute a temperature use this option. The default is 3 which is a correction factor for an ensemble of velocities with zero total linear momentum. </P> <P>The <I>dynamic</I> keyword determines whether the number of atoms N in the compute group is re-computed each time a temperature is computed. Only compute styles that compute a temperature use this option. By default, N is assumed to be constant. If you are adding atoms to the system (see the <A HREF = "fix_pour.html">fix pour</A> or <A HREF = "fix_deposit.html">fix deposit</A> commands) or expect atoms to be lost (e.g. due to evaporation), then this option can be used to insure the temperature is correctly normalized. </P> <P><B>Restrictions:</B> none </P> <P><B>Related commands:</B> </P> <P><A HREF = "compute.html">compute</A> </P> <P><B>Default:</B> </P> <P>The option defaults are extra = 3 and dynamic = no. </P> </HTML>