numpy.tril
- numpy. tril ( m, k=0 ) [source]
-
Lower triangle of an array.
Return a copy of an array with elements above the
k
-th diagonal zeroed. For arrays withndim
exceeding 2,tril
will apply to the final two axes.- 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 andk > 0
is above.
- Returns
-
- tril ndarray, shape (…, M, N)
-
Lower triangle of
m
, of same shape and data-type asm
.
See also
-
triu
-
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]])
>>> np.tril(np.arange(3*4*5).reshape(3, 4, 5)) array([[[ 0, 0, 0, 0, 0], [ 5, 6, 0, 0, 0], [10, 11, 12, 0, 0], [15, 16, 17, 18, 0]], [[20, 0, 0, 0, 0], [25, 26, 0, 0, 0], [30, 31, 32, 0, 0], [35, 36, 37, 38, 0]], [[40, 0, 0, 0, 0], [45, 46, 0, 0, 0], [50, 51, 52, 0, 0], [55, 56, 57, 58, 0]]])
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https://numpy.org/doc/1.22/reference/generated/numpy.tril.html