#!/usr/bin/env bash

# Author: Daniel S. Karls (karl0100 |AT| umn DOT edu), University of Minnesota
# Date: 10/10/2014

# This example Test Driver computes the cohesive energy and equilibrium
# lattice constant for an FCC argon lattice using Polak-Ribiere
# conjugate gradient static minimization in LAMMPS and an initial guess
# at the equilibrium lattice spacing supplied by the user through pipeline.stdin.tpl.

# Define function which outputs to stderr
echoerr() { echo "$@" 1>&2; }

# Read the KIM Model name and initial lattice constant from pipeline.stdin.tpl
# (the former is passed using @< MODELNAME >@, which the
# pipeline will automatically fill in once a compatible Model is found).
echo "Please enter a KIM Model name:"
read modelname
echo "Please enter an initial lattice constant (Angstroms):"
read initial_lattice_constant

# Replace the string 'sed_model_string' in the lammp.in.template input file
# script template with the name of the KIM Model being used.  Also replace
# the string 'sed_initial_lattice_constant_string' with the value supplied
# through stdin.
# The resulting  file will be stored in the Test Result folder (which may be
# referenced as the 'output' directory).
thisdir=`dirname "$0"` # The directory of this Test Driver executable
sed -e "s/sed_model_string/"$modelname"/"                                  \
    -e "s/sed_initial_lattice_constant_string/$initial_lattice_constant/"  \
    ""$thisdir"/lammps.in.template" > output/lammps.in

# Run LAMMPS using the lammps.in input file and write the output to output/lammps.log
lammps < output/lammps.in > output/lammps.log

# Parse the LAMMPS output log and extract the final pressure (to indicate how converged it is to 0),
# cohesive energy, and equilibrium lattice constant.
numberoflines=`awk 'END{print NR}' output/lammps.log`
finalpressure=`awk "NR==$numberoflines-2" output/lammps.log | awk '{print $(NF-1)}'`
ecohesive=`awk "NR==$numberoflines-1" output/lammps.log | awk '{print $(NF-1)}'`
latticeconstant=`awk "NR==$numberoflines" output/lammps.log | awk '{print $(NF-1)}'`

# Check that the results we obtained are actually numbers (in case there was a LAMMPS error of some sort)
if ! [[ $finalpressure =~ ^[0-9.e-]+ ]] ; then
    echo "Error: Final pressure parsed from LAMMPS log is not a numeric value.  Check the LAMMPS log for errors.  Exiting..."
    echoerr "Error: Final pressure parsed from LAMMPS log is not a numeric value.  Check the LAMMPS log for errors.  Exiting..."
    exit 1
elif ! [[ $ecohesive =~ ^[0-9.e-]+ ]] ; then
    echo "Error: Cohesive energy parsed from LAMMPS log is not a numeric value.  Check the LAMMPS log for errors.  Exiting..."
    echoerr "Error: Cohesive energy parsed from LAMMPS log is not a numeric value.  Check the LAMMPS log for errors.  Exiting..."
    exit 1
elif ! [[ $latticeconstant =~ ^[0-9.e-]+ ]] ; then
    echo "Error: Equilibrium lattice constant parsed from LAMMPS log is not a numeric value.  Check the LAMMPS log for errors.  Exiting..."
    echoerr "Error: Equilibrium lattice constant parsed from LAMMPS log is not a numeric value.  Check the LAMMPS log for errors.  Exiting..."
    exit 1
fi

sed -e "s/_LATCONST_/${latticeconstant}/"  \
    -e "s/_ECOHESIVE_/${ecohesive}/"       \
    ""$thisdir"/results.edn.tpl" > output/results.edn

# Write final pressure to file to indicate level of convergence
echo "The final pressure corresponding to the cohesive energy and lattice constant given in results.edn is:" > output/finalpressure.txt
echo "${finalpressure} bar" >> output/finalpressure.txt