first few pieces of pair style python

examples/python/in.pair_python_hybrid

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+# 3d Lennard-Jones hybrid
+
+units		lj
+atom_style	atomic
+
+lattice		fcc 0.8442
+region		box block 0 10 0 10 0 10
+create_box	2 box
+create_atoms	1 box
+mass		* 1.0
+
+velocity	all create 3.0 87287
+
+pair_style	hybrid lj/cut 2.5 python 2.5
+pair_coeff	* * python lj-melt-potential.py lj NULL
+pair_coeff      * 2 lj/cut 1.0 1.0
+
+neighbor	0.3 bin
+neigh_modify	every 10 delay 0 check no
+
+fix		1 all nve
+
+thermo		50
+run		250
+
+write_data      hybrid.data
+write_restart   hybrid.restart
+
+clear
+
+read_restart    hybrid.restart
+
+pair_style	hybrid lj/cut 2.5 python 2.5
+pair_coeff	* * python lj-melt-potential.py lj NULL
+pair_coeff      * 2 lj/cut 1.0 1.0
+
+fix		1 all nve
+
+thermo		50
+run		250
+
+clear
+
+units		lj
+atom_style	atomic
+
+read_data       hybrid.data
+
+pair_style	hybrid lj/cut 2.5 python 2.5
+pair_coeff	* * python lj-melt-potential.py lj NULL
+pair_coeff      * 2 lj/cut 1.0 1.0
+
+neighbor	0.3 bin
+neigh_modify	every 10 delay 0 check no
+
+fix		1 all nve
+
+thermo		50
+run		250
+

examples/python/in.pair_python_melt

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+# 3d Lennard-Jones melt
+
+units		lj
+atom_style	atomic
+
+lattice		fcc 0.8442
+region		box block 0 10 0 10 0 10
+create_box	1 box
+create_atoms	1 box
+mass		1 1.0
+
+velocity	all create 3.0 87287
+
+pair_style	python 2.5
+pair_coeff	* * lj-melt-potential.py lj
+
+neighbor	0.3 bin
+neigh_modify	every 10 delay 0 check no
+
+fix		1 all nve
+
+thermo		50
+run		250
+
+write_data      melt.data
+write_restart   melt.restart
+
+clear
+
+read_restart    melt.restart
+
+pair_style	python 2.5
+pair_coeff	* * lj-melt-potential.py lj
+
+fix		1 all nve
+
+thermo		50
+run		250
+
+clear
+
+units		lj
+atom_style	atomic
+
+read_data       melt.data
+
+pair_style	python 2.5
+pair_coeff	* * lj-melt-potential.py lj
+
+neighbor	0.3 bin
+neigh_modify	every 10 delay 0 check no
+
+fix		1 all nve
+
+thermo		50
+run		250
+

examples/python/lj-melt-potential.py

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+from __future__ import print_function
+
+class LAMMPSLJCutPotential(object):
+
+    def __init__(self):
+        self.pmap=dict()
+        # coefficients: epsilon, sigma
+        self.coeff = {'lj'  : {'lj'  : (1.0,1.0),
+                               'NULL': (0.0,1.0)},
+                      'NULL': {'lj'  : (0.0,1.0),
+                               'NULL': (0.0,1.0)}}
+
+    def map_coeff(self,type,name):
+        if self.coeff.has_key(name):
+           print("map type %d to name %s" % (type,name))
+           self.pmap[type] = name
+        else:
+           print("cannot match atom type",name)
+
+    def compute_force(self,r,itype,jtype,factor_lj):
+        return 0.0
+
+    def compute_energy(self,r,itype,jtype,factor_lj):
+        return 0.0
+
+lammps_pair_style = LAMMPSLJCutPotential()
+print ("lj-melt potential file loaded")
+