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a) The EWAH library is reference implementation provided to support the paper. SDSL is a library that collects together a bunch of such papers. It isn't odd tha
by cbsmith 10y ago
a) The EWAH library is reference implementation provided to support the paper. SDSL is a library that collects together a bunch of such papers. It isn't odd that there is no mention of SDSL. It is a bit odd that SDSL makes no mention of any of Daniel's work.
b) I haven't used SDSL much or RRR bit vectors, but IIRC it's more designed for maximum compactness as well as quick popcount & select type operations. You can do that with EWAH, but a lot of the power of EWAH and its ilk (BBC, WAH, etc.) is with set operators like AND, OR & ANDNOT. Does SDSL have the same kind of optimizations?
- pelario 10y agoThe bitmaps in SDSL are indexed to support rank and select queries: How many 1's are from the beginning until position i, and conversely, which is the position of the j-th 1) [it uses popcount but is beyond it] So yes, the problems they are solving are different, even though the input data is the same.