PARQUET-1609: Specify which xxhash carefully (#143)
The hash function "xxhash" is actually a number of different hash
functions including xxHash, XXH64, XXH32, and XXH3. Additionally,
these hash functions accept "seeds", as most modern hash functions do,
including MurmurHash variants.
This patch specifies that the BloomFilter hash function default is
XXH64 with a seed of 0. It omits the confusing note about the ISA and
different variants of xxHash, since XXH64 is apparently
architecture-independent.
diff --git a/BloomFilter.md b/BloomFilter.md
index a01481e..e51b412 100644
--- a/BloomFilter.md
+++ b/BloomFilter.md
@@ -108,9 +108,9 @@
#### Hash Function
The function used to hash values in the initial implementation is
-[xxHash](https://cyan4973.github.io/xxHash/), using the least-significant 64 bits version of the
-function on the x86-64 platform. Note that a given variant, such as XXHash64, shall produces same
-output irrespective of the cpu/os used, though different variants may produce different values.
+[xxHash](https://cyan4973.github.io/xxHash/), using the function XXH64 with a
+seed of 0 and [following the specification version
+0.1.1](https://github.com/Cyan4973/xxHash/blob/v0.7.0/doc/xxhash_spec.md).
#### Build a Bloom filter
The fact that exactly eight bits are checked during each lookup means that these filters
