code: def _amplify(ui_mat, alpha=1.0):
      """Exponentially amplify values of similarity matrix"""
      if alpha == 1.0:
          return ui_mat
  
      for i, w in enumerate(ui_mat.data):
          ui_mat.data[i] = w**alpha if w > 0 else -((-w) ** alpha)
      return ui_mat
  
imports: import multiprocessing
  import numpy
  from scipy.sparse import csr_matrix, coo_matrix
  from ..recommender import Recommender
  from ...exception import ScoreException
  from ...utils import get_rng
  from ...utils.fast_sparse_funcs import inplace_csr_row_normalize_l2
  from .similarity import compute_similarity, compute_score, compute_score_single
label_desc: Use image node_id 2 for calling a global function with example usage: _amplify(ui_mat, alpha) and returns: ui_mat, ui_mat