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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@7735 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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sjplimp
2012-02-09 18:04:37 +00:00
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35
doc/balance.html
View File

@ -88,14 +88,16 @@ balancing.
</P>
<CENTER><IMG SRC = "JPG/balance.jpg">
</CENTER>
<P>When the balance command completes, it prints out the change in
"imbalance factor". The imbalance factor is defined as the maximum
number of particles owned by any processor, divided by the average
number of particles per processor. Thus an imbalance factor of 1.0 is
perfect balance. For 10000 particles running on 10 processors, if the
most heavily loaded processor has 1200 particles, then the factor is
1.2, meaning there is a 20% imbalance. The change in the maximum
number of particles (on any processor) is also printed.
<P>When the balance command completes, it prints out the final positions
of all cutting planes in each of the 3 dimensions (as fractions of the
box length). It also prints statistics about its results, including
the change in "imbalance factor". This factor is defined as the
maximum number of particles owned by any processor, divided by the
average number of particles per processor. Thus an imbalance factor
of 1.0 is perfect balance. For 10000 particles running on 10
processors, if the most heavily loaded processor has 1200 particles,
then the factor is 1.2, meaning there is a 20% imbalance. The change
in the maximum number of particles (on any processor) is also printed.
</P>
<P>IMPORTANT NOTE: This command attempts to minimize the imbalance
factor, as defined above. But because of the topology constraint that
@ -163,12 +165,13 @@ balance y dynamic 1 10 xxxxx 1.2
balance y dynamic 50 1 x 1.2
</PRE>
<P>A rebalance operation in a single dimension is performed using an
iterative "diffusive" load-balancing algorithm. One iteration (which
is repeated <I>Niter</I> times), works as follows. Assume there are Px
processors in the x dimension. This defines Px slices of the
simulation, each of which contains Py*Pz processors. The task is to
adjust the position of the Px-1 cuts between slices, leaving the end
cuts unchanged (left and right edges of the simulation box).
iterative "diffusive" load-balancing algorithm <A HREF = "#Cybenko">(Cybenko)</A>.
One iteration on a dimension (which is repeated <I>Niter</I> times), works
as follows. Assume there are Px processors in the x dimension. This
defines Px slices of the simulation, each of which contains Py*Pz
processors. The task is to adjust the position of the Px-1 cuts
between slices, leaving the end cuts unchanged (left and right edges
of the simulation box).
</P>
<P>The iteration beings by calculating the number of atoms within each of
the Px slices. Then for each slice, its atom count is compared to its
@ -201,6 +204,8 @@ appear in <I>dimstr</I> for the <I>dynamic</I> keyword.
</P>
<HR>
<P>add a citation and image
<A NAME = "Cybenko"></A>
<P><B>(Cybenko)</B> Cybenko, J Par Dist Comp, 7, 279-301 (1989).
</P>
</HTML>

34
doc/balance.txt
View File

@ -81,14 +81,16 @@ balancing.
:c,image(JPG/balance.jpg)
When the balance command completes, it prints out the change in
"imbalance factor". The imbalance factor is defined as the maximum
number of particles owned by any processor, divided by the average
number of particles per processor. Thus an imbalance factor of 1.0 is
perfect balance. For 10000 particles running on 10 processors, if the
most heavily loaded processor has 1200 particles, then the factor is
1.2, meaning there is a 20% imbalance. The change in the maximum
number of particles (on any processor) is also printed.
When the balance command completes, it prints out the final positions
of all cutting planes in each of the 3 dimensions (as fractions of the
box length). It also prints statistics about its results, including
the change in "imbalance factor". This factor is defined as the
maximum number of particles owned by any processor, divided by the
average number of particles per processor. Thus an imbalance factor
of 1.0 is perfect balance. For 10000 particles running on 10
processors, if the most heavily loaded processor has 1200 particles,
then the factor is 1.2, meaning there is a 20% imbalance. The change
in the maximum number of particles (on any processor) is also printed.
IMPORTANT NOTE: This command attempts to minimize the imbalance
factor, as defined above. But because of the topology constraint that
@ -156,12 +158,13 @@ balance y dynamic 1 10 xxxxx 1.2
balance y dynamic 50 1 x 1.2 :pre
A rebalance operation in a single dimension is performed using an
iterative "diffusive" load-balancing algorithm. One iteration (which
is repeated {Niter} times), works as follows. Assume there are Px
processors in the x dimension. This defines Px slices of the
simulation, each of which contains Py*Pz processors. The task is to
adjust the position of the Px-1 cuts between slices, leaving the end
cuts unchanged (left and right edges of the simulation box).
iterative "diffusive" load-balancing algorithm "(Cybenko)"_#Cybenko.
One iteration on a dimension (which is repeated {Niter} times), works
as follows. Assume there are Px processors in the x dimension. This
defines Px slices of the simulation, each of which contains Py*Pz
processors. The task is to adjust the position of the Px-1 cuts
between slices, leaving the end cuts unchanged (left and right edges
of the simulation box).
The iteration beings by calculating the number of atoms within each of
the Px slices. Then for each slice, its atom count is compared to its
@ -194,4 +197,5 @@ appear in {dimstr} for the {dynamic} keyword.
:line
add a citation and image
:link(Cybenko)
[(Cybenko)] Cybenko, J Par Dist Comp, 7, 279-301 (1989).