code: def initialize_ray():
      
      if threading.current_thread().name == "MainThread":
          plasma_directory = None
          object_store_memory = os.environ.get("MODIN_MEMORY", None)
          if os.environ.get("MODIN_OUT_OF_CORE", "False").title() == "True":
              from tempfile import gettempdir
  
              plasma_directory = gettempdir()
              # We may have already set the memory from the environment variable, we don't
              # want to overwrite that value if we have.
              if object_store_memory is None:
                  # Round down to the nearest Gigabyte.
                  mem_bytes = ray.utils.get_system_memory() // 10 ** 9 * 10 ** 9
                  # Default to 8x memory for out of core
                  object_store_memory = 8 * mem_bytes
          # In case anything failed above, we can still improve the memory for Modin.
          if object_store_memory is None:
              # Round down to the nearest Gigabyte.
              object_store_memory = int(
                  0.6 * ray.utils.get_system_memory() // 10 ** 9 * 10 ** 9
              )
              # If the memory pool is smaller than 2GB, just use the default in ray.
              if object_store_memory == 0:
                  object_store_memory = None
          else:
              object_store_memory = int(object_store_memory)
          ray.init(
              include_webui=False,
              ignore_reinit_error=True,
              plasma_directory=plasma_directory,
              object_store_memory=object_store_memory,
          )
          # Register custom serializer for method objects to avoid warning message.
          # We serialize `MethodType` objects when we use AxisPartition operations.
          ray.register_custom_serializer(types.MethodType, use_pickle=True)
docs: Initializes ray based on environment variables and internal defaults.