code: def unvec(v):
      k = int(np.sqrt(len(v)))
      assert k * k == len(v)
      return v.reshape((k, k), order="F")
  
imports: from __future__ import annotations
  from statsmodels.compat.python import Literal, lrange
  import warnings
  import numpy
  import pandas
  from pandas import DataFrame
  from pandas.tseries import offsets
  from pandas.tseries.frequencies import to_offset
  from statsmodels.tools.data import _is_recarray, _is_using_pandas
  from statsmodels.tools.sm_exceptions import ValueWarning
  from statsmodels.tools.typing import NDArray
  from statsmodels.tools.validation import array_like, bool_like, int_like, string_like
label_desc: Use image node_id 11 for calling a global function with example usage: unvec(v) and returns: v