#!/bin/sh

# run from directory where this script is
cd `echo $0 | sed 's/\(.*\)\/.*/\1/'` # extract pathname
EXAMPLE_DIR=`pwd`

# check whether echo has the -e option
if test "`echo -e`" = "-e" ; then ECHO=echo ; else ECHO="echo -e" ; fi

$ECHO
$ECHO "$EXAMPLE_DIR : starting"
$ECHO
$ECHO "This example shows how to use pw.x to calculate the total energy"
$ECHO "of graphite including van der Waal Grimme D3 semi-empirical correction" 

# set the needed environment variables
. ../../../environment_variables

# required executables and pseudopotentials
BIN_LIST="pw.x"
PSEUDO_LIST="C.pbe-n-rrkjus_psl.0.1.UPF"

$ECHO
$ECHO "  executables directory: $BIN_DIR"
$ECHO "  pseudo directory:      $PSEUDO_DIR"
$ECHO "  temporary directory:   $TMP_DIR"
$ECHO "  checking that needed directories and files exist...\c"

# check for directories
for DIR in "$BIN_DIR" "$PSEUDO_DIR" ; do
    if test ! -d $DIR ; then 
        $ECHO
        $ECHO "ERROR: $DIR not existent or not a directory"
        $ECHO "Aborting"
        exit 1
    fi
done
for DIR in "$TMP_DIR" "$EXAMPLE_DIR/results" ; do
    if test ! -d $DIR ; then
        mkdir $DIR
    fi
done
cd $EXAMPLE_DIR/results

# check for executables
for FILE in $BIN_LIST ; do
    if test ! -x $BIN_DIR/$FILE ; then
        $ECHO
        $ECHO "ERROR: $BIN_DIR/$FILE not existent or not executable"
        $ECHO "Aborting"
        exit 1
    fi
done

# check for pseudopotentials
for FILE in $PSEUDO_LIST ; do
    if test ! -r $PSEUDO_DIR/$FILE ; then
       $ECHO
       $ECHO "Downloading $FILE to $PSEUDO_DIR...\c"
            $WGET $PSEUDO_DIR/$FILE $NETWORK_PSEUDO/$FILE 2> /dev/null
    fi
    if test $? != 0; then
        $ECHO
        $ECHO "ERROR: $PSEUDO_DIR/$FILE not existent or not readable"
        $ECHO "Aborting"
        exit 1
    fi
done
$ECHO " done"

# how to run executables
PW_COMMAND="$PARA_PREFIX $BIN_DIR/pw.x $PARA_POSTFIX"
$ECHO
$ECHO "  running pw.x as: $PW_COMMAND"
$ECHO

$ECHO
$ECHO "  running PBE Grimme D3 calculation for graphite\c"
$ECHO

# self-consistent calculation
cat > graphite_d3.in << EOF
&control
    calculation='scf',
    restart_mode='from_scratch',
    prefix='graphite'
    pseudo_dir = '$PSEUDO_DIR',
    outdir='$TMP_DIR'
 /
 &system
    ibrav = 0,
    celldm(1) =4.66,
    nat=  4,
    ntyp= 1,
    vdw_corr = 'dft-d3',
    ecutwfc = 37
    ecutrho = 318
 /
 &electrons
    conv_thr =1.0d-8
/
 &ions
/
CELL_PARAMETERS alat
1.0 0.0 0.0
-0.5 0.8660254037844386 0.0
0.0 0.0 3.60
ATOMIC_SPECIES
 C 12.011 C.pbe-n-rrkjus_psl.0.1.UPF
ATOMIC_POSITIONS crystal
 C 0.00000    1.00000    0.75000
 C 0.66667    0.33333    0.75000
 C 0.00000    1.00000    0.25000
 C 0.33333    0.66667    0.25000
K_POINTS AUTOMATIC
3 3 3 1 1 1
EOF
$ECHO "  running the scf calculation for graphite and Grimme D3 \c"
$PW_COMMAND < graphite_d3.in > graphite_d3.out
$ECHO " done"
grep -e ! graphite_d3.out | tail -1

# clean TMP_DIR
$ECHO "  cleaning $TMP_DIR...\c"
rm -rf $TMP_DIR/graphite*
$ECHO " done"

$ECHO
$ECHO "  running PBE Grimme D2 (london) calculation for graphite \c"
$ECHO

# self-consistent calculation
cat > graphite_d2.in << EOF
&control
    calculation='scf',
    restart_mode='from_scratch',
    prefix='graphite'
    pseudo_dir = '$PSEUDO_DIR',
    outdir='$TMP_DIR'
 /
 &system
    ibrav = 0,
    celldm(1) =4.66,
    nat=  4,
    ntyp= 1,
    vdw_corr = 'dft-d',
    ecutwfc = 37
    ecutrho = 318
 /
 &electrons
    conv_thr =1.0d-8
/
 &ions
/
CELL_PARAMETERS alat
1.0 0.0 0.0
-0.5 0.8660254037844386 0.0
0.0 0.0 3.60
ATOMIC_SPECIES
 C 12.011 C.pbe-n-rrkjus_psl.0.1.UPF
ATOMIC_POSITIONS crystal
 C 0.00000    1.00000    0.75000
 C 0.66667    0.33333    0.75000
 C 0.00000    1.00000    0.25000
 C 0.33333    0.66667    0.25000
K_POINTS AUTOMATIC
3 3 3 1 1 1
EOF
$ECHO "  running the scf calculation for graphite Grimme D2\c"
$PW_COMMAND < graphite_d2.in > graphite_d2.out
$ECHO " done"
grep -e ! graphite_d2.out | tail -1

# clean TMP_DIR
$ECHO "  cleaning $TMP_DIR...\c"
rm -rf $TMP_DIR/graphite*
$ECHO " done"

$ECHO "$EXAMPLE_DIR : done"
