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triu

Returns an array with all elements below the k-th diagonal set to zero.

Parameters:

Name Type Description Default
x COO

The input array.

required
k int

The diagonal below which elements are set to zero. The default is zero, which corresponds to the main diagonal.

0

Returns:

Type Description
COO

The output upper-triangular matrix.

Raises:

Type Description
ValueError

If x doesn't have zero fill-values.

See Also
Source code in sparse/numba_backend/_coo/common.py
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def triu(x, k=0):
    """
    Returns an array with all elements below the k-th diagonal set to zero.

    Parameters
    ----------
    x : COO
        The input array.
    k : int, optional
        The diagonal below which elements are set to zero. The default is
        zero, which corresponds to the main diagonal.

    Returns
    -------
    COO
        The output upper-triangular matrix.

    Raises
    ------
    ValueError
        If `x` doesn't have zero fill-values.

    See Also
    --------
    - [`numpy.triu`][] : NumPy equivalent function
    """
    from .core import COO

    check_zero_fill_value(x)

    if not x.ndim >= 2:
        raise NotImplementedError("sparse.triu is not implemented for scalars or 1-D arrays.")

    mask = x.coords[-2] + k <= x.coords[-1]

    coords = x.coords[:, mask]
    data = x.data[mask]

    return COO(coords, data, shape=x.shape, has_duplicates=False, sorted=True)