code: def bartlett(M):
      if M < 1:
          return ivy.array([])
      if M == 1:
          return ivy.ones(M, dtype=ivy.float64)
      res = ivy.arange(0, M)
      res = ivy.where(
          ivy.less_equal(res, (M - 1) / 2.0),
          2.0 * res / (M - 1),
          2.0 - 2.0 * res / (M - 1),
      )
      return res
  
imports: import ivy
  from ivy.functional.frontends.jax.func_wrapper import to_ivy_arrays_and_back, handle_jax_dtype
  from ivy.functional.frontends.jax.numpy import promote_types_of_jax_inputs
label_desc: Use image node_id 6 for calling a global function with example usage: bartlett(M) and returns: res, ivy, ivy