Notes on Precomputed preallocated vs. non-preallocated

We had both ideas and implemented both to compare.

Non-preallocated keeps a pageRanks array in each node, as well as a bitmap.
First element in pageRanks array is then for non-block aligned first part. This means each bitmap boundary requires an extra precomputed value. 

By concanetating all the bitmaps into one, we can store fewer precomputed values and still have them cover all bitmaps. 
It saves some space.
It requires some more popcount operations in the queries, but only about double (because popcount at beginning as well as end), which is a O(1) factor, I believe, or is is O(log n)?

Compare for varying block sizes of both
2 graphs:
	Wall time of both types for varying block size
	Memory Usage for both types for varyins block sizes
Possibly more graphs (perhaps in appendix) displaying Cache Misses, BMs, TLB Misses.


We first had the complicated ideas, then figured maybe the extra computations weren't worth it.
Then we implemented the non-preallocated case, found it was better.
THen we figured maybe the page-aligning wasn't worth it, and then tried that.