code: def triu(m, k=0):
      """
      Make a copy of a matrix with elements below the k-th diagonal zeroed.
  
      Parameters
      ----------
      m : array_like
          Matrix whose elements to return
      k : int, optional
          Diagonal below which to zero elements.
          `k` == 0 is the main diagonal, `k` < 0 subdiagonal and
          `k` > 0 superdiagonal.
  
      Returns
      -------
      triu : ndarray
          Return matrix with zeroed elements below the k-th diagonal and has
          same shape and type as `m`.
  
      Examples
      --------
      >>> from scipy.linalg import triu
      >>> triu([[1,2,3],[4,5,6],[7,8,9],[10,11,12]], -1)
      array([[ 1,  2,  3],
             [ 4,  5,  6],
             [ 0,  8,  9],
             [ 0,  0, 12]])
  
      """
      m = np.asarray(m)
      out = (1 - tri(m.shape[0], m.shape[1], k - 1, m.dtype.char)) * m
      return out
  
imports: from __future__ import division, print_function, absolute_import
  import math
  import numpy
  from scipy._lib.six import xrange
  from scipy._lib.six import string_types
  from numpy.lib.stride_tricks import as_strided
label_desc: Use image node_id 3 for calling a global function with example usage: triu(m, k) and returns: out