code: def f(dfnum, dfden, size=None, dtype=float):
      """F distribution.
  
      Returns an array of samples drawn from the f distribution. Its probability
      density function is defined as
  
      .. math::
          f(x) = \\frac{1}{B(\\frac{d_1}{2},\\frac{d_2}{2})} \
              \\left(\\frac{d_1}{d_2}\\right)^{\\frac{d_1}{2}} \
              x^{\\frac{d_1}{2}-1} \
              \\left(1+\\frac{d_1}{d_2}x\\right) \
              ^{-\\frac{d_1+d_2}{2}}.
  
      Args:
          dfnum (float or array_like of floats): Parameter of the f distribution
              :math:`d_1`.
          dfden (float or array_like of floats): Parameter of the f distribution
              :math:`d_2`.
          size (int or tuple of ints): The shape of the array. If ``None``, a
              zero-dimensional array is generated.
          dtype: Data type specifier. Only :class:`numpy.float32` and
              :class:`numpy.float64` types are allowed.
  
      Returns:
          cupy.ndarray: Samples drawn from the f distribution.
  
      .. seealso::
          :func:`numpy.random.f`
      """
      rs = _generator.get_random_state()
      return rs.f(dfnum, dfden, size, dtype)
  
imports: from cupy.random import _generator
  from cupy import _util
label_desc: Use image node_id 6 for calling a global function with example usage: f(dfnum, dfden, size, dtype) and returns: rs