torch (version 0.8.1)

torch_gather: Gather

Description

Gather

Usage

torch_gather(self, dim, index, sparse_grad = FALSE)

Arguments

self

(Tensor) the source tensor

dim

(int) the axis along which to index

index

(LongTensor) the indices of elements to gather

sparse_grad

(bool,optional) If TRUE, gradient w.r.t. input will be a sparse tensor.

gather(input, dim, index, sparse_grad=FALSE) -> Tensor

Gathers values along an axis specified by dim.

For a 3-D tensor the output is specified by::

out[i][j][k] = input[index[i][j][k]][j][k]  # if dim == 0
out[i][j][k] = input[i][index[i][j][k]][k]  # if dim == 1
out[i][j][k] = input[i][j][index[i][j][k]]  # if dim == 2

If input is an n-dimensional tensor with size $(x_0,x_1...,x_{i-1},x_i,x_{i+1},...,x_{n-1})$ and dim = i, then index must be an $n$-dimensional tensor with size $(x_0,x_1,...,x_{i-1},y,x_{i+1},...,x_{n-1})$ where $y\ge 1$ and out will have the same size as index.

Examples

if (torch_is_installed()) {

t = torch_tensor(matrix(c(1,2,3,4), ncol = 2, byrow = TRUE))
torch_gather(t, 2, torch_tensor(matrix(c(1,1,2,1), ncol = 2, byrow=TRUE), dtype = torch_int64()))
}