code: def g_rosenbrock(x, a=1, b=100):
      """Gradietn of rosenbrock example"""
  
      g = np.array(
          [
              -2 * a - 4 * b * x[0] * (-x[0] ** 2 + x[1]) + 2 * x[0],
              b * (-2 * x[0] ** 2 + 2 * x[1]),
          ]
      )
  
      return g
  
imports: from cuml.tsa.batched_lbfgs import batched_fmin_lbfgs_b
  from cuml.internals.safe_imports import cpu_only_import
label_desc: Use image node_id 2 for calling a global function with example usage: g_rosenbrock(x, a, b) and returns: g