code: def ref_vat_noise(r, base_axis, eps):
      base_axis = base_axis + r.ndim * (base_axis < 0)
      shape = r.shape
      r = r.reshape(shape[0:base_axis] + (np.prod(shape[base_axis:]),))
      r = r / np.sqrt(np.sum(r**2, axis=base_axis)).reshape(
          shape[0:base_axis] + (1,)
      )
      r = r.reshape(shape).astype(np.float32)
      return eps * r
  
file_path: nnabla/python/test/function/test_vat_noise.py
imports: import pytest
  import numpy
  import nnabla
  import nnabla.functions
  from nbla_test_utils import list_context
  from nnabla.testing import assert_allclose
label_desc: Use image node_id 1 for calling a global function with example usage: ref_vat_noise(r, base_axis, eps) and returns: unknown