This is what I am trying to do.

`tensor_A[:, tensor_B]`

torch::Tensor cholesky_vector = torch::ones({5, 6});

torch::Tensor cholesky_diag_index = torch::arange(da, torch::dtype(torch::kLong)) + 1;

torch::Tensor cholesky_diag_index_2 = (cholesky_diag_index * (cholesky_diag_index + 1)) / 2 - 1;

int main () {

std::cout << cholesky_vector.index({ Slice(None, cholesky_diag_index_2.to(torch::kLong)) });

}

`cholesky_vector`

is tensor_A and `cholesky_diag_index_2`

is tensor_B.

I’m getting

```
/home/iii/tor/m_gym/multiv_normal.cpp:54:39: error: no matching function for call to ‘at::Tensor::index(<brace-enclosed initializer list>)’
54 | std::cout << cholesky_vector.index({ Slice(None, cholesky_diag_index_2.to(torch::kLong)) });
| ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /home/iii/tor/m_gym/libtorch/include/ATen/core/Tensor.h:3,
from /home/iii/tor/m_gym/libtorch/include/ATen/Tensor.h:3,
from /home/iii/tor/m_gym/libtorch/include/torch/csrc/autograd/function_hook.h:3,
from /home/iii/tor/m_gym/libtorch/include/torch/csrc/autograd/cpp_hook.h:2,
from /home/iii/tor/m_gym/libtorch/include/torch/csrc/autograd/variable.h:6,
```

etc.

I am able to index with the second tensor, but I am not able to use it at all with `Slice`

. Would I be able to maybe convert the tensor to a list or array or something that the slice would not have a problem with?