Added elastic constant example at finite temperature

git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@14105 f3b2605a-c512-4ea7-a41b-209d697bcdaa

examples/ELASTIC_T/in.elastic

@@ -52,8 +52,16 @@ include init.mod
 
 # Compute initial state
 
+variable thermostat equal 1
 include potential.mod
 run ${nequil}
+
+if "${adiabatic} == 1" &
+then "variable thermostat equal 0" &
+else "variable thermostat equal 1"
+
+print ${thermostat}
+
 include potential.mod
 run ${nrun}
 

examples/ELASTIC_T/init.mod

@@ -12,17 +12,18 @@ variable cfac equal 1.0e-4
 variable cunits string GPa
 
 # Define MD parameters
-variable nevery equal 10
-variable nrepeat equal 10
-variable nfreq equal ${nevery}*${nrepeat}
-variable nthermo equal ${nfreq}
-variable nequil equal 10*${nthermo}
-variable nrun equal 3*${nthermo}
-variable temp equal 2000.0
-variable timestep equal 0.001
-variable mass1 equal 28.06
-variable tdamp equal 0.01
-variable seed equal 123457
+variable nevery equal 10                  # sampling interval
+variable nrepeat equal 10                 # number of samples
+variable nfreq equal ${nevery}*${nrepeat} # length of one average
+variable nthermo equal ${nfreq}           # interval for thermo output
+variable nequil equal 10*${nthermo}       # length of equilibration run
+variable nrun equal 3*${nthermo}          # length of equilibrated run
+variable temp equal 2000.0                # temperature of initial sample
+variable timestep equal 0.001             # timestep
+variable mass1 equal 28.06                # mass
+variable adiabatic equal 0                # adiabatic (1) or isothermal (2)
+variable tdamp equal 0.01                 # time constant for thermostat
+variable seed equal 123457                # seed for thermostat
 
 # generate the box and atom positions using a diamond lattice
 variable a equal 5.431
@@ -34,4 +35,6 @@ region		box prism 0 3.0 0 3.0 0 3.0 0.0 0.0 0.0
 create_box	1 box
 create_atoms	1 box
 mass 1 ${mass1}
+velocity	all create ${temp} 87287
+
 

examples/ELASTIC_T/potential.mod

@@ -22,6 +22,7 @@ thermo_modify norm no
 
 timestep ${timestep}
 fix 4 all nve
-fix 5 all langevin ${temp} ${temp} ${tdamp} ${seed}
+if "${thermostat} == 1" then &
+   "fix 5 all langevin ${temp} ${temp} ${tdamp} ${seed}"