# load the pw.x input from file
load_fromPWI ../pw.si.scf.in

# open a file for writing resulting total energies
set fid [open Etot-vs-ecutwfc.dat w]

# loop over different "ecut" values
foreach ecut [seq 12 4 40] {

    # name of I/O files: $name.in & $name.out
    set name pw.Si.scf.ecutwfc-$ecut

    # set the pw.x "ecutwfc" variable
    SYSTEM "ecutwfc = $ecut"

    # run the pw.x calculation
    runPW $name.in

    # extract the "total energy" and write it to file
    set Etot [pwo_totene $name.out]
    puts $fid "$ecut $Etot"
} 

close $fid


# plot the result with gnuplot
exec gnuplot plot.gp