parameters: (x, n)
return_statement: return val
docstring: r"""
      Return the factorial of `x` to the `n` falling.
  
      This is defined as:
  
      .. math::   x^\underline n = (x)_n = x (x-1) \cdots (x-n+1)
  
      This can more efficiently calculate ratios of factorials, since:
  
      n!/m! == falling_factorial(n, n-m)
  
      where n >= m
  
      skipping the factors that cancel out
  
      the usual factorial n! == ff(n, n)
docstring_summary: r"""
      Return the factorial of `x` to the `n` falling.
docstring_tokens: r Return the factorial of x to the n falling .
function: def _falling_factorial(x, n):
      r"""
      Return the factorial of `x` to the `n` falling.
  
      This is defined as:
  
      .. math::   x^\underline n = (x)_n = x (x-1) \cdots (x-n+1)
  
      This can more efficiently calculate ratios of factorials, since:
  
      n!/m! == falling_factorial(n, n-m)
  
      where n >= m
  
      skipping the factors that cancel out
  
      the usual factorial n! == ff(n, n)
      """
      val = 1
      for k in range(x - n + 1, x + 1):
          val *= k
      return val
function_tokens: def _falling_factorial ( x , n ) : val = 1 for k in range ( x - n + 1 , x + 1 ) : val *= k return val