make python functions examples more complete by adding exception handling and initializing variables

examples/python/funcs.py

@@ -8,17 +8,21 @@ def loop(N,cut0,thresh,lmpptr):
   from lammps import lammps
   lmp = lammps(ptr=lmpptr)
   natoms = lmp.get_natoms()
-  
-  for i in range(N):
-    cut = cut0 + i*0.1
 
-    lmp.set_variable("cut",cut)                 # set a variable in LAMMPS
+  try:
+    for i in range(N):
+      cut = cut0 + i*0.1
 
-    lmp.command("pair_style lj/cut ${cut}")     # LAMMPS command
+      lmp.set_variable("cut",cut)                 # set a variable in LAMMPS
-    #lmp.command("pair_style lj/cut %d" % cut)  # LAMMPS command option
+
+      lmp.command("pair_style lj/cut ${cut}")     # LAMMPS command
+      #lmp.command("pair_style lj/cut %d" % cut)  # LAMMPS command option
+
+      lmp.command("pair_coeff * * 1.0 1.0")       # ditto
+      lmp.command("run 10")                       # ditto
+      pe = lmp.extract_compute("thermo_pe",0,0)   # extract total PE from LAMMPS
+      print("PE",pe/natoms,thresh)
+      if pe/natoms < thresh: return
+  except Exception as e:
+    print("LOOP error:", e)
 
-    lmp.command("pair_coeff * * 1.0 1.0")       # ditto
-    lmp.command("run 10")                       # ditto
-    pe = lmp.extract_compute("thermo_pe",0,0)   # extract total PE from LAMMPS
-    print("PE",pe/natoms,thresh)
-    if pe/natoms < thresh: return

examples/python/in.python

@@ -28,6 +28,7 @@ python          simple here """
 from __future__ import print_function
 
 def simple():
+  foo = 0
   print("Inside simple function")
   try:
     foo += 1