class_docstr: Dataset for a class of objects, where each datapoint is a SceneInstanceDataset.
class_docstr_tok: ["Dataset","for","a","class","of","objects",",","where","each","datapoint","is","a","SceneInstanceDataset","."]
code: def change_sampling_idx(self, sampling_size):
      if sampling_size == -1:
          self.sampling_idx = None
      else:
          self.sampling_idx = torch.randperm(self.total_pixels)[
              :sampling_size
          ]
  
file_path: insightface/reconstruction/PBIDR/code/datasets/dataset.py
imports: import os
  import torch
  import numpy
  import utils.general
  from utils import rend_util
label_desc: Use image node_id 5 for calling the IFDataset obj's underlying member method code with example usage: obj.change_sampling_idx(sampling_size) without return types