code: def _log_softmax(x, axis=1):
      if chainer.should_use_cudnn(">=auto"):
          xp = backend.get_array_module(x)
          if xp is cuda.cupy:
              return cudnn.softmax_forward(x, axis, _algorithm)
      log_z = logsumexp(x, axis)
      y = x - log_z
      return y
  
imports: import chainer
  from chainer import backend
  from chainer.backends import cuda
  from chainer import function_node
  import chainer.functions
  from chainer.utils import type_check
  import chainerx
label_desc: Use image node_id 2 for calling a global function with example usage: _log_softmax(x, axis) and returns: y, cudnn