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lammps/python/examples/plot.py
e000e4a04f45lammm-master-deprecated

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plot.py
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#!/usr/bin/env python -i
# preceeding line should have path for Python on your machine
# plot.py
# Purpose: plot Temp of running LAMMPS simulation via GnuPlot in Pizza.py
# Syntax: plot.py in.lammps Nfreq Nsteps compute-ID
# in.lammps = LAMMPS input script
# Nfreq = plot data point every this many steps
# Nsteps = run for this many steps
# compute-ID = ID of compute that calculates temperature
# (or any other scalar quantity)
import sys
sys.path.append("./pizza")
from gnu import gnu
# parse command line
argv = sys.argv
if len(argv) != 5:
print "Syntax: plot.py in.lammps Nfreq Nsteps compute-ID"
sys.exit()
infile = sys.argv[1]
nfreq = int(sys.argv[2])
nsteps = int(sys.argv[3])
compute = sys.argv[4]
me = 0
# uncomment if running in parallel via Pypar
#import pypar
#me = pypar.rank()
#nprocs = pypar.size()
from lammps import lammps
lmp = lammps()
# run infile all at once
# assumed to have no run command in it
lmp.file(infile)
lmp.command("thermo %d" % nfreq)
# initial 0-step run to generate initial 1-point plot
lmp.command("run 0 pre yes post no")
value = lmp.extract_compute(compute,0,0)
ntimestep = 0
xaxis = [ntimestep]
yaxis = [value]
# wrapper on GnuPlot via Pizza.py gnu tool
# just proc 0 handles plotting
if me == 0:
gn = gnu()
gn.plot(xaxis,yaxis)
gn.xrange(0,nsteps)
gn.title(compute,"Timestep","Temperature")
# run nfreq steps at a time w/out pre/post, query compute, refresh plot
while ntimestep < nsteps:
lmp.command("run %d pre no post no" % nfreq)
ntimestep += nfreq
value = lmp.extract_compute(compute,0,0)
xaxis.append(ntimestep)
yaxis.append(value)
if me == 0: gn.plot(xaxis,yaxis)
lmp.command("run 0 pre no post yes")
# uncomment if running in parallel via Pypar
#print "Proc %d out of %d procs has" % (me,nprocs), lmp
#pypar.finalize()
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