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

python/examples/demo.py

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+#!/usr/local/bin/python -i
+# preceeding line should have path for Python on your machine
+
+# demo.py
+# Purpose: illustrate use of many library interface commands
+# Syntax:  demo.py
+#          uses in.demo as LAMMPS input script
+
+import sys
+
+# parse command line
+
+argv = sys.argv
+if len(argv) != 1:
+  print "Syntax: demo.py"
+  sys.exit()
+
+me = 0
+# uncomment if running in parallel via Pypar
+#import pypar
+#me = pypar.rank()
+#nprocs = pypar.size()
+
+from lammps import lammps
+from lammps import LMPINT as INT
+from lammps import LMPDOUBLE as DOUBLE
+from lammps import LMPIPTR as IPTR
+from lammps import LMPDPTR as DPTR
+from lammps import LMPDPTRPTR as DPTRPTR
+
+lmp = lammps()
+
+# test out various library functions after running in.demo
+
+lmp.file("in.demo")
+
+if me == 0: print "\nPython output:"
+
+natoms = lmp.extract_global("natoms",DOUBLE)
+mass = lmp.extract_atom("mass",DPTR)
+x = lmp.extract_atom("x",DPTRPTR)
+print "Natoms, mass, x[0][0] coord =",natoms,mass[1],x[0][0]
+
+temp = lmp.extract_compute("thermo_temp",0,0)
+print "Temperature from compute =",temp
+
+eng = lmp.extract_variable("eng",None,0)
+print "Energy from equal-style variable =",eng
+
+vy = lmp.extract_variable("vy","all",1)
+print "Velocity component from atom-style variable =",vy[1]
+
+natoms = lmp.get_natoms()
+print "Natoms from get_natoms =",natoms
+
+xc = lmp.get_coords()
+print "Global coords from get_coords =",xc[0],xc[1],xc[31]
+
+xc[0] = xc[0] + 1.0
+lmp.put_coords(xc)
+
+print "Changed x[0][0] via put_coords =",x[0][0]
+
+# uncomment if running in parallel via Pypar
+#print "Proc %d out of %d procs has" % (me,nprocs), lmp
+#pypar.finalize()