Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

5. Version history: We recommend the latest version SZ 0.5.10 11 (a.k.a., SZh)

  • SZ 0.2-0.4 Compression ratio is the same as SZ 0.5. The key difference is different implementation ways, such that SZ 0.5 is much faster than SZ 0.2-0.4.
  • SZ 0.5.1 Support version checking

...

  • SZ 0.5.9 optimize the offset by using simple right-shifting method. Experiments show that this cannot improve compression ratio actually, because simple right-shifting actually make each data be multiplied by 2^{-k}, where k is # right-shifting bits. The pros is to save bits because of more leading-zero bytes, but the cons is much more required bits to save. A good solution is SZ 0.5.10 11 (or SZh)!
  • SZ 0.5.10 (a.k.a., SZh) optimizes 10 optimizes the offset by using the optimized formula of computing the median_value based on optimized right-shifting method. Anyway, SZh improves compression ratio a lot for hard-to-compress datasets. (Hard-to-compress datasets refer to the cases whose compression ratios are usually very limited)
  • SZ 0.5.11 (a.k.a., SZh) improved SZ 0.5.10 on the level of guaranteeing user-specified error bounds. In a very few cases, SZ 0.5.10 cannot guarantee the error-bounds to a certain user-specified level. For example, when absolute error bound = 1E-6, the maximum decompression error may be 0.01(>>1E-6) because of the huge value range even in the optimized segments such that the normalized data cannot reach the required precision even stoaring all of the 64 or 32 mantissa bits. SZ 0.5.11 fixed the problem well, with degraded compression ratio less than 1% in that case. 

6. Download

-->>> Code download <<<-- (soon, pending DoE approval of distribution licence)

...