class_docstr: Exponential Linear Unit.
class_docstr_tok: ["Exponential","Linear","Unit","."]
code: def forward_gpu(self, inputs):
      if self.alpha < 0:
          self.retain_inputs((0,))
      (x,) = inputs
      y = cuda.elementwise(
          "T x, T alpha",
          "T y",
          "y = x > 0 ? x : (T)(alpha * expm1(x))",
          "elu_fwd",
      )(x, self.alpha)
      self.retain_outputs((0,))
      return (y,)
  
file_path: chainer/chainer/functions/activation/elu.py
imports: import numpy
  from chainer.backends import cuda
  from chainer import function_node
  from chainer import utils
  from chainer.utils import type_check
label_desc: Use image node_id 4 for calling the ELU obj's underlying member method code with example usage: obj.forward_gpu(inputs) and returns: y