code: def qr_destroy(la):
      """Get QR decomposition of `la[0]`.
  
      Parameters
      ----------
      la : list of numpy.ndarray
          Run QR decomposition on the first elements of `la`. Must not be empty.
  
      Returns
      -------
      (numpy.ndarray, numpy.ndarray)
          Matrices :math:`Q` and :math:`R`.
  
      Notes
      -----
      Using this function is less memory intense than calling `scipy.linalg.qr(la[0])`,
      because the memory used in `la[0]` is reclaimed earlier. This makes a difference when
      decomposing very large arrays, where every memory copy counts.
  
      Warnings
      --------
      Content of `la` as well as `la[0]` gets destroyed in the process. Again, for memory-effiency reasons.
  
      """
      a = np.asfortranarray(la[0])
      del la[0], la  # now `a` is the only reference to the input matrix
      m, n = a.shape
      # perform q, r = QR(a); code hacked out of scipy.linalg.qr
      logger.debug("computing QR of %s dense matrix", str(a.shape))
      (geqrf,) = get_lapack_funcs(("geqrf",), (a,))
      qr, tau, work, info = geqrf(a, lwork=-1, overwrite_a=True)
      qr, tau, work, info = geqrf(a, lwork=work[0], overwrite_a=True)
      del a  # free up mem
      assert info >= 0
      r = triu(qr[:n, :n])
      if m < n:  # rare case, #features < #topics
          qr = qr[:, :m]  # retains fortran order
      (gorgqr,) = get_lapack_funcs(("orgqr",), (qr,))
      q, work, info = gorgqr(qr, tau, lwork=-1, overwrite_a=True)
      q, work, info = gorgqr(qr, tau, lwork=work[0], overwrite_a=True)
      assert info >= 0, "qr failed"
      assert q.flags.f_contiguous
      return q, r
  
imports: from __future__ import with_statement
  import logging
  import math
  from gensim import utils
  import numpy
  import scipy.sparse
  from scipy.stats import entropy
  from scipy.linalg import get_blas_funcs, triu
  from scipy.linalg.lapack import get_lapack_funcs
  from scipy.special import psi
label_desc: Use image node_id 26 for calling a global function with example usage: qr_destroy(la) and returns: q,  r