numpy.triu(m, k=0) [source]
Upper triangle of an array. Return a copy of a matrix with the elements below the k-th diagonal zeroed. Please refer to the documentation for tril for further details. See also
tril
lower triangle of an array Examples >>> np.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]])