numpy.tri()

numpy.tri(N, M=None, k=0, dtype=) [source]

An array with ones at and below the given diagonal and zeros elsewhere.

Parameters:

Parameters:	N : int Number of rows in the array. M : int, optional Number of columns in the array. By default, `M` is taken equal to `N`. k : int, optional The sub-diagonal at and below which the array is filled. `k` = 0 is the main diagonal, while `k` < 0 is below it, and `k` > 0 is above. The default is 0. dtype : dtype, optional Data type of the returned array. The default is float.
Returns:	tri : ndarray of shape (N, M) Array with its lower triangle filled with ones and zero elsewhere; in other words `T[i,j] == 1` for `i <= j + k`, 0 otherwise.

N : int

Number of rows in the array.

M : int, optional

Number of columns in the array. By default, M is taken equal to N.

k : int, optional

The sub-diagonal at and below which the array is filled. k = 0 is the main diagonal, while k < 0 is below it, and k > 0 is above. The default is 0.

dtype : dtype, optional

Data type of the returned array. The default is float.

Returns:

tri : ndarray of shape (N, M)

Array with its lower triangle filled with ones and zero elsewhere; in other words T[i,j] == 1 for i <= j + k, 0 otherwise.

Examples

>>> np.tri(3, 5, 2, dtype=int)
array([[1, 1, 1, 0, 0],
       [1, 1, 1, 1, 0],
       [1, 1, 1, 1, 1]])

>>> np.tri(3, 5, -1)
array([[ 0.,  0.,  0.,  0.,  0.],
       [ 1.,  0.,  0.,  0.,  0.],
       [ 1.,  1.,  0.,  0.,  0.]])

Links:

https://docs.scipy.org/doc/numpy-1.11.0/reference/generated/numpy.tri.html

doc_NumPy

2017-01-10 18:19:03

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