Commit 31d2ab1f authored by Martin Perdacher's avatar Martin Perdacher

Merge branch 'master' of gitlab.cs.univie.ac.at:martinp16cs/hilbertJoin

parents a53c88e8 be2acaf7
### AVX-512 instructions
_What is the correct setting of parameters for uniform distributed data?_
There are two parameters, _KBLOCK_ and _stripes_. You can vary and play with them, but throughout our experiments we have always used _KBLOCK=4_ and _stripes=14_ which are the default settings for any kind of distribution. For uniform distributed data _KBLOCK=16_ is faster, but the variation of _stripes_ has no effect.
There are two parameters, _KBLOCK_ and _stripes_. Throughout our experiments we have always used _KBLOCK=4_ and _stripes=14_ which are the default settings for any kind of distribution. For uniform distributed data _KBLOCK=16_ is faster, but the variation of _stripes_ has no effect.
_Why do you use AVX-512 instructions?_
If we apply our Hilbert-curve in Intel or GNU compilers, auto-vectorization will get eliminated. Writing code with AVX instructions simulates the behaviour of having an implemented auto-vectorized approach. Nevertheless, we belive that future compilers will profit from the locality assumptions of the Hilbert curve.
......@@ -13,11 +13,13 @@ _What are the Parameters KBLOCK and STRIPES?_
_How to set KBLOCK and STRIPES?_
KBLOCK should be smaller then the dimension of the dataset. Best fitting values for stripes are: $`1,2,5,14,41 (=((3^j)+1)/2)`$.
KBLOCK should be smaller then the dimension of the dataset. Within our distance calculation, we check after KBLOCK dimensions whether we have exceeded $`\varepsilon^2`$ or not.
Best fitting values for active dimesnions are $`0,1,2,3,4,5`$ which corresponds to $`1,2,5,14,41 (=((3^j)+1)/2)`$ stripes, (for more details see paper Section 3.1 "Determination of the Bounds")
In our experiments (see paper) we _always_ use the following setting:
- KBLOCK=4
- STRIPES=14
- active dimensions=3, which are exactly 14 stripes
For uniform data we suggest to use the following parameter settings:
- KBLOCK=16
......
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