git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@3266 f3b2605a-c512-4ea7-a41b-209d697bcdaa

This commit is contained in:
sjplimp 2009-10-30 19:28:00 +00:00
parent 53000e9966
commit efd2c26122
2 changed files with 38 additions and 34 deletions

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@ -92,9 +92,10 @@ run is as follows:
event replica shares state with all replicas event replica shares state with all replicas
</PRE> </PRE>
<P>Before this loop begins, the state of the system on replica 0 is <P>Before this loop begins, the state of the system on replica 0 is
quenched (an energy minimization, see below) and the resulting shared with all replicas, so that all replicas begin from the same
coordinates are shared with all replicas, so that all replicas begin initial state. The first basin is identified by quenching (an energy
from the same initial state. minimization, see below) the initial state and storing the resulting
coordinates for reference.
</P> </P>
<P>In the first stage, dephasing is performed by each replica <P>In the first stage, dephasing is performed by each replica
independently to eliminate correlations between replicas. This is independently to eliminate correlations between replicas. This is
@ -111,16 +112,16 @@ with arguments that have the same meaning as their counterparts in the
<P>In the second stage, each replica runs dynamics continuously, stopping <P>In the second stage, each replica runs dynamics continuously, stopping
every <I>t_event</I> steps to check if a transition event has occurred. every <I>t_event</I> steps to check if a transition event has occurred.
This check is performed by quenching the system and comparing the This check is performed by quenching the system and comparing the
resulting atom coordinates to the coordinates of the previous event. resulting atom coordinates to the coordinates from the previous basin.
The first time through the PRD loop, the "previous event" is the The first time through the PRD loop, the "previous basin" is the set
initial state of the system. of quenched coordinates from the initial state of the system.
</P> </P>
<P>A quench is an energy minimization and is performed by whichever <P>A quench is an energy minimization and is performed by whichever
algorithm has been defined by the <A HREF = "min_style.html">min_style</A> command. algorithm has been defined by the <A HREF = "min_style.html">min_style</A> command.
Minimization parameters may be set via the Minimization parameters may be set via the
<A HREF = "min_modify.html">min_modify</A> command and by the <I>min</I> keyword of the <A HREF = "min_modify.html">min_modify</A> command and by the <I>min</I> keyword of the
PRD command. The latter are the settings that would be used with the PRD command. The latter are the settings that would be used with the
<A HREF = "minimize.html">minimize</A> command. Note that yypically, you do not <A HREF = "minimize.html">minimize</A> command. Note that typically, you do not
need to perform a highly-converged minimization to detect a transition need to perform a highly-converged minimization to detect a transition
event. event.
</P> </P>
@ -135,10 +136,11 @@ If so, an "event" has occurred.
</P> </P>
<P>In the third stage, the replica on which the event occurred continues <P>In the third stage, the replica on which the event occurred continues
to run dynamics to search for correlated events. This is done by to run dynamics to search for correlated events. This is done by
running dynamics for <I>t_correlate</I> steps, quenching, and checking if running dynamics for <I>t_correlate</I> steps, quenching every <I>t_event</I>
another event has occurred. The first time no correlated event steps, and checking if another event has occurred. The first time no
occurs, the final state of the system is shared with all replicas, and correlated event occurs, the final state of the system is shared with
the outer loop begins again. all replicas, the new basin reference coordinates are updated with the
quenched state, and the outer loop begins again.
</P> </P>
<HR> <HR>
@ -168,8 +170,8 @@ replicas are running independently. The clock represents the real
time that effectively elapses during a PRD simulation of <I>N</I> steps on time that effectively elapses during a PRD simulation of <I>N</I> steps on
M replicas. If most of the PRD run is spent in the second stage of M replicas. If most of the PRD run is spent in the second stage of
the loop above, searching for infrequent events, then the clock will the loop above, searching for infrequent events, then the clock will
advance nearly N*M steps. Note The advance nearly N*M steps. Note the clock time between events will be
clock time between events will be drawn from p(t). drawn from p(t).
</P> </P>
<P>The event number is a counter that increments with each event, whether <P>The event number is a counter that increments with each event, whether
it is uncorrelated or correlated. it is uncorrelated or correlated.
@ -224,15 +226,15 @@ no correlated events are found, this means it contains a snapshot of
the system at time T + <I>t_correlate</I>, where T is the time at which the the system at time T + <I>t_correlate</I>, where T is the time at which the
uncorrelated event occurred. If correlated events were found, then it uncorrelated event occurred. If correlated events were found, then it
contains a snapshot of the system at time T + <I>t_correlate</I>, where T contains a snapshot of the system at time T + <I>t_correlate</I>, where T
is the time of the last correlated event. Note that the state of the is the time of the last correlated event.
system is not quenched when written to the restart file.
</P> </P>
<P>The restart frequency specified in the <A HREF = "restart.html">restart</A> command <P>The restart frequency specified in the <A HREF = "restart.html">restart</A> command
is interpreted differently when performing a PRD run. It does not is interpreted differently when performing a PRD run. It does not
mean the timestep interval between restart files. Instead it means an mean the timestep interval between restart files. Instead it means an
event interval for uncorrelated events. Thus a frequency of 1 means event interval for uncorrelated events. Thus a frequency of 1 means
write a restart file every time an uncorrelated event occurs. A frequency write a restart file every time an uncorrelated event occurs. A
of 10 means write a restart file every 10th uncorrelated event. frequency of 10 means write a restart file every 10th uncorrelated
event.
</P> </P>
<P>When an input script reads a restart file from a previous PRD run, the <P>When an input script reads a restart file from a previous PRD run, the
new script can be run on a different number of replicas or processors. new script can be run on a different number of replicas or processors.

View File

@ -79,9 +79,10 @@ while (time remains):
event replica shares state with all replicas :pre event replica shares state with all replicas :pre
Before this loop begins, the state of the system on replica 0 is Before this loop begins, the state of the system on replica 0 is
quenched (an energy minimization, see below) and the resulting shared with all replicas, so that all replicas begin from the same
coordinates are shared with all replicas, so that all replicas begin initial state. The first basin is identified by quenching (an energy
from the same initial state. minimization, see below) the initial state and storing the resulting
coordinates for reference.
In the first stage, dephasing is performed by each replica In the first stage, dephasing is performed by each replica
independently to eliminate correlations between replicas. This is independently to eliminate correlations between replicas. This is
@ -98,16 +99,16 @@ with arguments that have the same meaning as their counterparts in the
In the second stage, each replica runs dynamics continuously, stopping In the second stage, each replica runs dynamics continuously, stopping
every {t_event} steps to check if a transition event has occurred. every {t_event} steps to check if a transition event has occurred.
This check is performed by quenching the system and comparing the This check is performed by quenching the system and comparing the
resulting atom coordinates to the coordinates of the previous event. resulting atom coordinates to the coordinates from the previous basin.
The first time through the PRD loop, the "previous event" is the The first time through the PRD loop, the "previous basin" is the set
initial state of the system. of quenched coordinates from the initial state of the system.
A quench is an energy minimization and is performed by whichever A quench is an energy minimization and is performed by whichever
algorithm has been defined by the "min_style"_min_style.html command. algorithm has been defined by the "min_style"_min_style.html command.
Minimization parameters may be set via the Minimization parameters may be set via the
"min_modify"_min_modify.html command and by the {min} keyword of the "min_modify"_min_modify.html command and by the {min} keyword of the
PRD command. The latter are the settings that would be used with the PRD command. The latter are the settings that would be used with the
"minimize"_minimize.html command. Note that yypically, you do not "minimize"_minimize.html command. Note that typically, you do not
need to perform a highly-converged minimization to detect a transition need to perform a highly-converged minimization to detect a transition
event. event.
@ -122,10 +123,11 @@ If so, an "event" has occurred.
In the third stage, the replica on which the event occurred continues In the third stage, the replica on which the event occurred continues
to run dynamics to search for correlated events. This is done by to run dynamics to search for correlated events. This is done by
running dynamics for {t_correlate} steps, quenching, and checking if running dynamics for {t_correlate} steps, quenching every {t_event}
another event has occurred. The first time no correlated event steps, and checking if another event has occurred. The first time no
occurs, the final state of the system is shared with all replicas, and correlated event occurs, the final state of the system is shared with
the outer loop begins again. all replicas, the new basin reference coordinates are updated with the
quenched state, and the outer loop begins again.
:line :line
@ -155,8 +157,8 @@ replicas are running independently. The clock represents the real
time that effectively elapses during a PRD simulation of {N} steps on time that effectively elapses during a PRD simulation of {N} steps on
M replicas. If most of the PRD run is spent in the second stage of M replicas. If most of the PRD run is spent in the second stage of
the loop above, searching for infrequent events, then the clock will the loop above, searching for infrequent events, then the clock will
advance nearly N*M steps. Note The advance nearly N*M steps. Note the clock time between events will be
clock time between events will be drawn from p(t). drawn from p(t).
The event number is a counter that increments with each event, whether The event number is a counter that increments with each event, whether
it is uncorrelated or correlated. it is uncorrelated or correlated.
@ -211,15 +213,15 @@ no correlated events are found, this means it contains a snapshot of
the system at time T + {t_correlate}, where T is the time at which the the system at time T + {t_correlate}, where T is the time at which the
uncorrelated event occurred. If correlated events were found, then it uncorrelated event occurred. If correlated events were found, then it
contains a snapshot of the system at time T + {t_correlate}, where T contains a snapshot of the system at time T + {t_correlate}, where T
is the time of the last correlated event. Note that the state of the is the time of the last correlated event.
system is not quenched when written to the restart file.
The restart frequency specified in the "restart"_restart.html command The restart frequency specified in the "restart"_restart.html command
is interpreted differently when performing a PRD run. It does not is interpreted differently when performing a PRD run. It does not
mean the timestep interval between restart files. Instead it means an mean the timestep interval between restart files. Instead it means an
event interval for uncorrelated events. Thus a frequency of 1 means event interval for uncorrelated events. Thus a frequency of 1 means
write a restart file every time an uncorrelated event occurs. A frequency write a restart file every time an uncorrelated event occurs. A
of 10 means write a restart file every 10th uncorrelated event. frequency of 10 means write a restart file every 10th uncorrelated
event.
When an input script reads a restart file from a previous PRD run, the When an input script reads a restart file from a previous PRD run, the
new script can be run on a different number of replicas or processors. new script can be run on a different number of replicas or processors.