#!/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()