mindspore.ops.tril_indices

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mindspore.ops.tril_indices(row, col, offset=0, *, dtype=mstype.int64)[source]

Return a 2-by-N tensor containing the indices of the lower triangular elements of a row * col matrix. The first row of the Tensor contains row coordinates, and the second row contains column coordinates. The coordinates are sorted by rows and then columns.

Note

When running on CUDA, row * col must be less than 2^59 to prevent overflow during calculation.

Parameters

  • row (int) – number of rows in the 2-D matrix.

  • col (int) – number of columns in the 2-D matrix.

  • offset (int, optional) –

    Diagonal offset. Default 0 .

    • When offset is a positive integer, the diagonal is shifted upward.

    • When offset is a negative integer, the diagonal is shifted downward.

Keyword Arguments

dtype (mindspore.dtype, optional) – The specified type of output tensor. An optional data type of mindspore.int32 and mindspore.int64. Default mstype.int64 .

Returns

Tensor

Supported Platforms:

Ascend GPU CPU

Examples

>>> import mindspore
>>> # case 1: By default, offset=0, all elements on and below the main diagonal are retained.
>>> mindspore.ops.tril_indices(3, 2, 0)
Tensor(shape=[2, 5], dtype=Int64, value=
[[0, 1, 1, 2, 2],
 [0, 0, 1, 0, 1]])
>>>
>>> # case 2: Offset=1, the indices on and below the first sub-diagonal above the main diagonal are returned.
>>> mindspore.ops.tril_indices(3, 2, 1)
Tensor(shape=[2, 6], dtype=Int64, value=
[[0, 0, 1, 1, 2, 2],
 [0, 1, 0, 1, 0, 1]])
>>>
>>> # case 3: Offset=-1, the indices on and below the first sub-diagonal below the main diagonal are returned.
>>> mindspore.ops.tril_indices(3, 2, -1)
Tensor(shape=[2, 3], dtype=Int64, value=
[[1, 2, 2],
 [0, 0, 1]])