#!/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 and postprocessing codes to make a"
$ECHO "contour plot in the [110] plane of the charge density for Si, and to"
$ECHO "plot the band structure of Si."

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

# required executables and pseudopotentials
BIN_LIST="pw.x pp.x plotrho.x bands.x plotband.x"
PSEUDO_LIST="Si.pz-vbc.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 gnuplot
GP_COMMAND=`which gnuplot 2>/dev/null`
if [ "$GP_COMMAND" = "" ]; then
        $ECHO
        $ECHO "gnuplot not in PATH"
        $ECHO "Results will not be plotted"
fi

# 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=" mpirun -n 4 $BIN_DIR/pw.x $PARA_POSTFIX"
PP_COMMAND="$PARA_PREFIX $BIN_DIR/pp.x $PARA_POSTFIX"
PW_COMMAND="$PARA_PREFIX $BIN_DIR/pw.x $PARA_POSTFIX"
PLOTRHO_COMMAND="$BIN_DIR/plotrho.x"
BANDS_COMMAND="mpirun -n 4 $BIN_DIR/bands.x $PARA_POSTFIX"
PLOTBAND_COMMAND="$BIN_DIR/plotband.x"
$ECHO
$ECHO "  running pw.x as      : $PW_COMMAND"
$ECHO "  running pp.x as      : $PP_COMMAND"
$ECHO "  running plotrho.x as : $PLOTRHO_COMMAND"
$ECHO "  running bands.x as   : $BANDS_COMMAND"
$ECHO "  running plotband.x as: $PLOTBAND_COMMAND"
$ECHO

# self-consistent calculation
cat > si.scf.in << EOF
 &control
    calculation='scf'
    restart_mode='from_scratch',
    prefix='si'
    pseudo_dir = '$PSEUDO_DIR/',
    outdir='$TMP_DIR/'
    wf_collect = .true.
 /
 &system
                        ibrav = 0,
                          nat = 8,
                        ntyp = 1,
                     ecutwfc = 20.0 ,
                     ecutrho = 80 ,
 /
 &electrons
    conv_thr =  1.0d-8
    mixing_beta = 0.7
 /
CELL_PARAMETERS angstrom 
     5.314000000    0.000000000    0.000000000 
     0.000000000    5.314000000    0.000000000 
     0.000000000    0.000000000    5.314000000 
ATOMIC_SPECIES
   Si   28.08600  Si.pz-vbc.UPF 
ATOMIC_POSITIONS crystal 
   Si      0.000000000    0.000000000    0.000000000    
   Si      0.000000000    0.500000000    0.500000000    
   Si      0.500000000    0.500000000    0.000000000    
   Si      0.500000000    0.000000000    0.500000000    
   Si      0.750000000    0.250000000    0.750000000    
   Si      0.250000000    0.250000000    0.250000000    
   Si      0.250000000    0.750000000    0.750000000    
   Si      0.750000000    0.750000000    0.250000000    
K_POINTS automatic 
  2 2 2   0 0 0 
EOF
$ECHO "  running the scf calculation...\c"
$PW_COMMAND < si.scf.in > si.scf.out
check_failure $?
$ECHO " done"


# band structure calculation along high-symmetry lines
cat > si.band.in << EOF
 &control
    calculation='bands'
    pseudo_dir = '$PSEUDO_DIR/',
    outdir='$TMP_DIR/',
    prefix='si'
    wf_collect = .true.
 /
&system
                        ibrav = 0,
                          nat = 8,
                        ntyp = 1,
                     ecutwfc = 20.0 ,
                     ecutrho = 80 ,
nbnd = 8
 /
 &electrons
    conv_thr =  1.0d-8
    mixing_beta = 0.7
 /
CELL_PARAMETERS angstrom 
     5.314000000    0.000000000    0.000000000 
     0.000000000    5.314000000    0.000000000 
     0.000000000    0.000000000    5.314000000 
ATOMIC_SPECIES
   Si   28.08600  Si.pz-vbc.UPF 
ATOMIC_POSITIONS crystal 
   Si      0.000000000    0.000000000    0.000000000    
   Si      0.000000000    0.500000000    0.500000000    
   Si      0.500000000    0.500000000    0.000000000    
   Si      0.500000000    0.000000000    0.500000000    
   Si      0.750000000    0.250000000    0.750000000    
   Si      0.250000000    0.250000000    0.250000000    
   Si      0.250000000    0.750000000    0.750000000    
   Si      0.750000000    0.750000000    0.250000000    
K_POINTS tpiba_b
  5
  L 20
  gG 20
  X 0
  1.0 1.0 0.0 30
  gG  1
EOF
$ECHO "  running the band-structure calculation for Si...\c"
$PW_COMMAND < si.band.in > si.band.out
check_failure $?
$ECHO " done"

# post-processing for band structure
cat > si.bands.in << EOF
 &bands
    prefix  = 'si'
    outdir = '$TMP_DIR/'
    filband = 'sibands.dat'
    lsym=.true.,
 /
EOF
$ECHO "  running the post-processing for band structure...\c"
$BANDS_COMMAND < si.bands.in > si.bands.out
check_failure $?
$ECHO " done"

# plotband.x
cat > si.plotband.in << EOF
sibands.dat
-6.0 10
sibands.xmgr
sibands.ps
6.255
1.0 6.255
EOF
$ECHO "  running plotband.x to generate sibands.ps...\c"
$PLOTBAND_COMMAND < si.plotband.in > si.plotband.out
check_failure $?
$ECHO " done"