This is so cool! Thanks so much, I plan to go through it in full when I have some time. For now, I was wondering if the red circled matrix multiplication should actually be reversed, and the vector should be column (ie. matrix*column, instead of row*matrix). I know the end result is equivalent but it seems in order to be consistent it should be switched, ie in every other example of a vector with leg sticking out leftward its a column vector? maybe this really doesnt matter since I can just turn the page upside down and then b would be on the left with a leg sticking out to the right..., but the fact that A dot b = b.T dot A is itself an interesting fact.
Oops, yep. I initially had the tensor diagrams for that multiplication the other way around (vector then matrix). I changed them to be more conventional, but forgot that. As you say you can just move the tensors any which way and get the same answer so long as the connectivity is the same, though it would be Ab=bTAT or yi=∑jAijbj=∑jbjAij=∑jbjATji to keep the legs connected the same way.
This is so cool! Thanks so much, I plan to go through it in full when I have some time. For now, I was wondering if the red circled matrix multiplication should actually be reversed, and the vector should be column (ie. matrix*column, instead of row*matrix). I know the end result is equivalent but it seems in order to be consistent it should be switched, ie in every other example of a vector with leg sticking out leftward its a column vector? maybe this really doesnt matter since I can just turn the page upside down and then b would be on the left with a leg sticking out to the right..., but the fact that A dot b = b.T dot A is itself an interesting fact.
Oops, yep. I initially had the tensor diagrams for that multiplication the other way around (vector then matrix). I changed them to be more conventional, but forgot that. As you say you can just move the tensors any which way and get the same answer so long as the connectivity is the same, though it would be Ab=bTAT or yi=∑jAijbj=∑jbjAij=∑jbjATji to keep the legs connected the same way.