code: def set_idx(self, labels, ref_labels):
      if not self.was_set_externally:
          self.a1, self.p, self.a2, self.n = lmu.get_all_pairs_indices(
              labels, ref_labels
          )
  
file_path: pytorch-metric-learning/src/pytorch_metric_learning/miners/hdc_miner.py
imports: import math
  import torch
  from ..utils import loss_and_miner_utils
  from .base_miner import BaseMiner
label_desc: Use image node_id 4 for calling the HDCMiner obj's underlying member method code with example usage: obj.set_idx(labels, ref_labels) without return types