Tensor::device() does not respect Tensor::to_device(...)

[jerry73204]

I ran into this issue when I'm working with multi-GPU training. Surprisingly, this test failed unexpectedly. The device() returns Cuda(1) after to_device(Cuda(0)). Suppose it an off-by-1 bug?

use tch::{Tensor, Device};

#[test]
fn test_device() {
    let x = Tensor::from(1).to_device(Device::Cuda(0));
    assert_eq!(x.device(), Device::Cuda(0)); // actually returns Device::Cuda(1)
}

[LaurentMazare]

Thanks for catching this, I just pushed a fix for it (and will add some test although it won't run on CI as there are no gpus there).

[jerry73204]

Many thanks.