CDO

require 'cdo'

require 'jobqueue'

iFile                 = ARGV[0].nil? ? 'ifs_oper_T1279_2011010100.grb' : ARGV[0]

targetGridFile        = ARGV[1].nil? ? 'cell_grid-r2b07.nc'            : ARGV[1]

targetGridweightsFile = ARGV[2].nil? ? 'cell_weight-r2b07.nc'          : ARGV[2]

nWorkers              = ARGV[3].nil? ? 8                               : ARGV[3]

# lets work in debug mode

Cdo.debug = true

# create a queue with a predifined number of workers

jq = JobQueue.new(nWorkers)

# split the input file wrt to variable names,codes,levels,grids,timesteps,...

splitTag = "ifs2icon_skel_split_"

#Cdo.splitcode(:in => iFile, :out => splitTag,:options => '-f nc')

Cdo.splitname(:in => iFile, :out => splitTag,:options => '-f nc')

# collect Files form the split

files = Dir.glob("#{splitTag}*.nc")

# remap variables in parallel

files.each {|file|

  jq.push {

    basename = file[0..-(File.extname(file).size+1)]

    Cdo.remap(targetGridFile,targetGridweightsFile,

              :in => file,

              :out => "remapped_#{basename}.nc")

  }

}

jq.run

# Merge all the results together

Cdo.merge(:in => Dir.glob("remapped_*.nc").join(" "),:out => 'mergedResults.nc')