docstr: Perform the dequantization and rescaling of the weights of a given layer. After that operation the layer will
  be quantized again.
docstr_tok: ["Perform","the","dequantization","and","rescaling","of","the","weights","of","a","given","layer",".","After","that","operation","the","layer","will","be","quantized","again","."]
code: def _bnb_4bit_dequantize_and_rescale(self, target_layer, block_id):
      r"""
      Perform the dequantization and rescaling of the weights of a given layer. After that operation the layer will
      be quantized again.
      """
      if not is_bitsandbytes_available():
          raise ImportError(
              "Please install bitsandbytes to use this method."
          )
      import bitsandbytes as bnb
  
      dequant_weights = bnb.functional.dequantize_4bit(
          target_layer.weight.data, target_layer.weight.quant_state
      )
  
      dequant_weights.div_(
          2 ** int(block_id // self.config.rescale_every)
      )
  
      # re-quantize the model:
      # we need to put it first on CPU then back to the device
      # this will create an overhead :/
      # We set requires_grad=False as we cannot compute gradients on top of 4bit parameters anyway and to avoid
      # bugs with bnb
      quant_weight = bnb.nn.Params4bit(
          dequant_weights.to("cpu"), requires_grad=False
      ).to(dequant_weights.device)
      setattr(target_layer, "weight", quant_weight)
  
imports: import math
  from dataclasses import dataclass
  from pathlib import Path
  from typing import List, Optional, Tuple, Union
  import torch
  import torch.utils.checkpoint
  from torch import nn
  from torch.nn import CrossEntropyLoss
  from ...modeling_utils import PreTrainedModel
  from ...utils import ModelOutput, add_code_sample_docstrings, add_start_docstrings, add_start_docstrings_to_model_forward, is_bitsandbytes_available, is_ninja_available, is_torch_cuda_available, logging
  from .configuration_rwkv import RwkvConfig
label_desc: Use image node_id 6 for calling the RwkvModel obj's underlying member method code with example usage: obj._bnb_4bit_dequantize_and_rescale(target_layer, block_id) without return types