Function assign_to_checkpoint

Dreambooth/convertodiffv2.py:139–188

This does the final conversion step: take locally converted weights and apply a global renaming to them. It splits attention layers, and takes into account additional replacements that may arise. Assigns the weights to the new checkpoint.

(
    paths, checkpoint, old_checkpoint, attention_paths_to_split=None, additional_replacements=None, config=None
)

def assign_to_checkpoint(
    paths, checkpoint, old_checkpoint, attention_paths_to_split=None, additional_replacements=None, config=None
):
  """
  This does the final conversion step: take locally converted weights and apply a global renaming
  to them. It splits attention layers, and takes into account additional replacements
  that may arise.

  Assigns the weights to the new checkpoint.
  """
  assert isinstance(paths, list), "Paths should be a list of dicts containing 'old' and 'new' keys."

  # Splits the attention layers into three variables.
  if attention_paths_to_split is not None:
    for path, path_map in attention_paths_to_split.items():
      old_tensor = old_checkpoint[path]
      channels = old_tensor.shape[0] // 3

      target_shape = (-1, channels) if len(old_tensor.shape) == 3 else (-1)

      num_heads = old_tensor.shape[0] // config["num_head_channels"] // 3

      old_tensor = old_tensor.reshape((num_heads, 3 * channels // num_heads) + old_tensor.shape[1:])
      query, key, value = old_tensor.split(channels // num_heads, dim=1)

      checkpoint[path_map["query"]] = query.reshape(target_shape)
      checkpoint[path_map["key"]] = key.reshape(target_shape)
      checkpoint[path_map["value"]] = value.reshape(target_shape)

  for path in paths:
    new_path = path["new"]

    # These have already been assigned
    if attention_paths_to_split is not None and new_path in attention_paths_to_split:
      continue

    # Global renaming happens here
    new_path = new_path.replace("middle_block.0", "mid_block.resnets.0")
    new_path = new_path.replace("middle_block.1", "mid_block.attentions.0")
    new_path = new_path.replace("middle_block.2", "mid_block.resnets.1")

    if additional_replacements is not None:
      for replacement in additional_replacements:
        new_path = new_path.replace(replacement["old"], replacement["new"])

    # proj_attn.weight has to be converted from conv 1D to linear
    if "proj_attn.weight" in new_path:
      checkpoint[new_path] = old_checkpoint[path["old"]][:, :, 0]
    else:
      checkpoint[new_path] = old_checkpoint[path["old"]]


def conv_attn_to_linear(checkpoint):