# the number of availalbe cores
if [ "$CORES" == "quad" ]; then

   # create 4 arrays, each with ~25% of filenames
   NUM_FILE_LISTS='4'
   PROCESSED='0'

   # get size of each subset
    BASE_LIST_SIZE=$(((NUM_INPUT_FILES) / NUM_FILE_LISTS))
   LEFTOVER=$((NUM_INPUT_FILES % NUM_FILE_LISTS))

   # set up start elements and number of elements for all lists
   # list 0
   START_ELEMENT_0='0'
   NUMBER_OF_ELEMENTS_0=$((BASE_LIST_SIZE + (LEFTOVER > 0)))
   # keep track of number of files processed
   let "PROCESSED=$PROCESSED+$NUMBER_OF_ELEMENTS_0"
      
   # list 1   
   START_ELEMENT_1=$PROCESSED
   #let "START_ELEMENT_1=$START_ELEMENT_0+$NUMBER_OF_ELEMENTS_0"
   NUMBER_OF_ELEMENTS_1=$((BASE_LIST_SIZE + (LEFTOVER > 1)))
   let "PROCESSED=$PROCESSED+$NUMBER_OF_ELEMENTS_1"
 
   # list 2  
   START_ELEMENT_2=$PROCESSED
   NUMBER_OF_ELEMENTS_2=$((BASE_LIST_SIZE + (LEFTOVER > 2)))
   # keep track of number of files processed
   let "PROCESSED=$PROCESSED+$NUMBER_OF_ELEMENTS_2"
 
   # list 3  
   START_ELEMENT_3=$PROCESSED
   # assign the rest to this list
   let "NUMBER_OF_ELEMENTS_3=$NUM_INPUT_FILES-$PROCESSED"
   # keep track of number of files processed
   let "PROCESSED=$PROCESSED+$NUMBER_OF_ELEMENTS_3"

      # call functions to process stats
      run_stats_program  $SET  $FOLD  $START_ELEMENT_0  $NUMBER_OF_ELEMENTS_0 &
      # to prevent terminal overrun
      sleep 2
      run_stats_program  $SET  $FOLD  $START_ELEMENT_1  $NUMBER_OF_ELEMENTS_1 &
      sleep 2
      run_stats_program  $SET  $FOLD  $START_ELEMENT_2  $NUMBER_OF_ELEMENTS_2 &
      sleep 2
      run_stats_program  $SET  $FOLD  $START_ELEMENT_3  $NUMBER_OF_ELEMENTS_3 &
      sleep 2
      # wait untill subshells have returned
      wait

 fi

function run_stats_program {

   # function args
   SET_F=$1
   FOLD_F=$2
   START_ELEMENT_F=$3
   NUMBER_OF_ELEMENTS_F=$4
   
   # get list of stats input files in fold directory
   STATS_INPUT_FILENAMES_F=($(ls  './'$SET_F'/'$FOLD_F'/'*'in.txt'))
 
   # create file list as subest of STATS_INPUT_FILENAMES_F
   FILE_LIST=("${STATS_INPUT_FILENAMES_F[@]:$START_ELEMENT_F:$NUMBER_OF_ELEMENTS_F}")

   for INPUT_FILE in "${FILE_LIST[@]}"
   do
      echo $INPUT_FILE
   done
}