# Tril_indices

Source:`R/gen-namespace-docs.R`

, `R/gen-namespace-examples.R`

, `R/wrapers.R`

`torch_tril_indices.Rd`

Tril_indices

## Arguments

- row
(

`int`

) number of rows in the 2-D matrix.- col
(

`int`

) number of columns in the 2-D matrix.- offset
(

`int`

) diagonal offset from the main diagonal. Default: if not provided, 0.- dtype
(

`torch.dtype`

, optional) the desired data type of returned tensor. Default: if`NULL`

,`torch_long`

.- device
(

`torch.device`

, optional) the desired device of returned tensor. Default: if`NULL`

, uses the current device for the default tensor type (see`torch_set_default_tensor_type`

).`device`

will be the CPU for CPU tensor types and the current CUDA device for CUDA tensor types.- layout
(

`torch.layout`

, optional) currently only support`torch_strided`

.

## tril_indices(row, col, offset=0, dtype=torch.long, device='cpu', layout=torch.strided) -> Tensor

Returns the indices of the lower triangular part of a `row`

-by-
`col`

matrix in a 2-by-N Tensor, where the first row contains row
coordinates of all indices and the second row contains column coordinates.
Indices are ordered based on rows and then columns.

The lower triangular part of the matrix is defined as the elements on and below the diagonal.

The argument `offset`

controls which diagonal to consider. If
`offset`

= 0, all elements on and below the main diagonal are
retained. A positive value includes just as many diagonals above the main
diagonal, and similarly a negative value excludes just as many diagonals below
the main diagonal. The main diagonal are the set of indices
\(\lbrace (i, i) \rbrace\) for \(i \in [0, \min\{d_{1}, d_{2}\} - 1]\)
where \(d_{1}, d_{2}\) are the dimensions of the matrix.

## Examples

```
if (torch_is_installed()) {
if (FALSE) {
a = torch_tril_indices(3, 3)
a
a = torch_tril_indices(4, 3, -1)
a
a = torch_tril_indices(4, 3, 1)
a
}
}
```