No compiler check for operation on different tensor type.

[npuichigo]

let a = Tensor::new(&[3u8], &candle::Device::Cpu)?;
let b = a / 4f64;

What's the value of tensor b? Wow, it's Ok(Tensor[0; u8]). Rust compiler rejects code like 3u8 / 4f64, while it's legal in tensor operation but return wrong result.

I can say these lines are wrong for cifar dataset, and all image here are just all zero u8.

candle/candle-datasets/src/vision/cifar.rs

Lines 84 to 86 in 8a05743

	let images = (Tensor::from_vec(buffer_images, (samples, 3, 32, 32), &Device::Cpu)?
	.to_dtype(DType::U8)?
	/ 255.)?;

Any insights on compiler check for operation on different type tensor? Or it's by design? @LaurentMazare

[LaurentMazare]

It's kind of by design though I agree that it's not ideal. The Tensor type does not expose the tensor dtypes so we cannot really express the constraints of a scalar multiplication or addition at run time. Still it's quite convenient to be able to say multiply the values in the tensor by a constant or add a constant, so affine operations using a f64 are supported for all tensors with "rounded" semantics.