if { [info exists rel_tol] && $rel_tol > 0 } {
   puts "\nChecking triangulation area (triarea command)..."
   set rel_err [expr abs([CheckTriArea result $area_eps])]
   if { $rel_err > $rel_tol } {
      puts "Error   : area by triangles differs from the actual area by $rel_err %"
   } else {
      if { [info exists max_rel_tol_diff] && $max_rel_tol_diff > 0} {
        checkreal "area difference" $rel_err $rel_tol $max_rel_tol_diff 0
      } else {
        if { $rel_tol > 1 && $rel_tol < 100 } {
          puts "Error: Improvement: The current area difference is $rel_err instead of $rel_tol"
        }
      }
   }
}

# to end a test script
puts "TEST COMPLETED"