code: def rsqrt(x):
      """Computes elementwise reciprocal of square root of input :math:`x_i`.
  
      .. math::
         y_i = {1 \\over \\sqrt x_i}.
  
      Args:
          x (:class:`~chainer.Variable` or :ref:`ndarray`): Input variable.
  
      Returns:
          ~chainer.Variable: Output variable.
  
      .. seealso:: :func:`~chainer.functions.sqrt`
      """
      xp = backend.get_array_module(x)
      if xp is numpy or xp is chainerx:
          return 1.0 / sqrt(x)
  
      # CuPy provides `rsqrt` which is faster than `1.0 / sqrt(x)`.
      return RsqrtGPU().apply((x,))[0]
  
imports: import numpy
  from chainer import backend
  from chainer.backends import cuda
  from chainer import function_node
  from chainer import utils
  from chainer.utils import type_check
  import chainerx
label_desc: Use image node_id 2 for calling a global function with example usage: rsqrt(x) and returns: RsqrtGPU, unknown