text: --
  -- Determine the Heads/Tails classifications from a numeric array
  --
  -- @param in_array A numeric array of numbers to determine the best
  --            bins based on the Heads/Tails method.
  --
  -- @param breaks The number of bins you want to find.
  --  
  --
  
  CREATE OR REPLACE FUNCTION @extschema@.CDB_HeadsTailsBins ( in_array NUMERIC[], breaks INT) RETURNS NUMERIC[] as $$ 
  DECLARE 
      element_count INT4; 
      arr_mean numeric; 
      i INT := 2; 
      reply numeric[]; 
  BEGIN 
      -- get the total size of our row
      element_count := array_upper(in_array, 1) - array_lower(in_array, 1); 
      -- ensure the ordering of in_array
      SELECT array_agg(e) INTO in_array FROM (SELECT unnest(in_array) e ORDER BY e) x;
      -- stop if no rows 
      IF element_count IS NULL THEN  
          RETURN NULL; 
      END IF; 
      -- stop if our breaks are more than our input array size
      IF element_count < breaks THEN  
          RETURN in_array; 
      END IF; 
  
      -- get our mean value
      SELECT avg(v) INTO arr_mean FROM (  SELECT unnest(in_array) as v ) x; 
  
      reply = Array[arr_mean];
      -- slice our bread
      LOOP  
          IF i > breaks THEN  EXIT;  END IF;  
          SELECT avg(e) INTO arr_mean FROM ( SELECT unnest(in_array) e) x WHERE e > reply[i-1];
          IF arr_mean IS NOT NULL THEN
              reply = array_append(reply, arr_mean);
          END IF;
          i := i+1; 
      END LOOP; 
      RETURN reply; 
  END; 
  $$ language plpgsql IMMUTABLE PARALLEL SAFE;
  