Readers should be warned that tensor decompositions are not unique

[FinAminToastCrunch]

This is regarding the portion on Tensor Train Decompositions:

https://harvard-edge.github.io/cs249r_book/contents/optimizations/optimizations.html#tensor-decomposition

I am recommending a change to this portion of the book. Tensor decompositions are not unique [1]; this can lead to confusion in the situation readers work in teams which use different hardware. I have encountered this precise conundrum in my research groups. I suggest putting a small note/footnote which lets readers know that performing a decomposition will not necessarily produce the same output across all hardware.

[1] Tensor Decomposition: Basics, Algorithms, and Recent Advances