I'm coming to the same conclusion. Inevitably, all my creativity winds up solving the "how to conserve space" and to a lesser degree the "how to minimize data moves" issues -- and none of my thinking in those areas is yielding a first-pass-scan benefit.

This is maddeningly entertaining because I can't count the number of times in my career I could optimize the inner algorithm if only I had the privilege of a pre-processing linear scan, which was too costly to be worth implementing.

Here, I have the exact opposite problem -- I am going to get a pre-processing linear scan, and I can't make use of it to optimize the inner process.

Somewhere, some deity of software development is having a huge guffaw at my expense.

:-)