code: def recall_at_k(r, k, all_pos_num):
      r = np.asfarray(r)[:k]
      return np.sum(r) / all_pos_num
  
file_path: dgl/examples/pytorch/NGCF/NGCF/utility/metrics.py
imports: import numpy
  from sklearn.metrics import roc_auc_score
label_desc: Use image node_id 7 for calling a global function with example usage: recall_at_k(r, k, all_pos_num) and returns: unknown