numpy.tri — NumPy v1.13 Manual (original) (raw)
numpy. tri(N, M=None, k=0, dtype=<type 'float'>)[source]¶
An array with ones at and below the given diagonal and zeros elsewhere.
| 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. |
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| 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.]])