mkmurn

#! /usr/bin/ruby

class Datum

  attr_reader :scaling, :energy

  def initialize( scaling, energy )
    @scaling = scaling
    @energy = energy
  end

end

data = []

murn_dirs = Dir.entries(".").select{ |dir| ( dir =~ /\d/ ) == 0 }
murn_dirs.each do |dir|
  Dir.chdir( dir ) do

    abort( "POSCAR not found in ./#{dir}" ) unless FileTest.exist?( "POSCAR" )
    poscar = File.new( "POSCAR", "r" )
    scaling = poscar.readlines[1].to_f
    poscar.close

    abort( "OUTCAR not found in ./#{dir}" ) unless FileTest.exist?( "OUTCAR" )
    outcar = File.new( "OUTCAR", "r" )
    final_energy = outcar.readlines.grep( /sigma/ )[-1]
    if final_energy.nil? then
      warn("No energy found in directory ./#{dir}")
    elsif
      energy = final_energy.strip.split(" ")[-1].to_f
      data << Datum.new( scaling, energy )
    end
    outcar.close

  end
end

abort("No directories found") if data.empty?

data.sort! { |a,b| a.scaling <=> b.scaling }

data[1..-2].each_with_index do | d, i | # check data set is concave at all internal points
  if data[i+1].energy > ( data[i].energy + data[i+2].energy ) / 2.0 then 
    warn "Not concave at lattice points:
          #{data[i].scaling} #{data[i].energy}
          #{data[i+1].scaling} #{data[i+1].energy}
          #{data[i+2].scaling} #{data[i+2].energy}" 
  end
end

puts "2\n1 1\n#{ data[0].scaling } #{ data[-1].scaling } 20"
puts "#{data.size}"
data.each{ |d| puts "#{ d.scaling } #{ d.energy }" }