Fix index used in example

[byoshimi-gmail]

Example should use k as loop variable and not j.

[plotfi]

Example should use k as loop variable and not j.

My understanding is that k is just an iteration count, but j is used to chase the next stride from the pointer chasing array. Some publications use “it” for the iterator and some use j:

https://arxiv.org/abs/1509.02308
https://www.stuffedcow.net/research/cudabmk