code: def rastrigin(x: np.ndarray) -> float:
      """Classical multimodal function."""
      cosi = float(np.sum(np.cos(2 * np.pi * x)))
      return float(10 * (len(x) - cosi) + sphere(x))
  
imports: from math import exp, sqrt, tanh
  import numpy
  import nevergrad.common.typing
  from nevergrad.common.decorators import Registry
label_desc: Use image node_id 17 for calling a global function with example usage: rastrigin(x) and returns: float