numpy.tril — NumPy v1.13 Manual (original) (raw)
Lower triangle of an array.
Return a copy of an array with elements above the _k_-th diagonal zeroed.
| Parameters: | m : array_like, shape (M, N) Input array. k : int, optional Diagonal above which to zero elements. k = 0 (the default) is the main diagonal, k < 0_ is below it and _k > 0 is above. |
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| Returns: | tril : ndarray, shape (M, N) Lower triangle of m, of same shape and data-type as m. |
See also
same thing, only for the upper triangle
Examples
np.tril([[1,2,3],[4,5,6],[7,8,9],[10,11,12]], -1) array([[ 0, 0, 0], [ 4, 0, 0], [ 7, 8, 0], [10, 11, 12]])