git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@5201 f3b2605a-c512-4ea7-a41b-209d697bcdaa

python/examples/plot.py

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+#!/usr/local/bin/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()