Re: Evolving Boost.ContainerHash

From: Peter Dimov (pdimov_at_[hidden])
Date: 2021-10-12 23:46:12

Vinnie Falco wrote:
> On Tue, Oct 12, 2021 at 4:26 PM Peter Dimov via Boost
> <boost_at_[hidden]> wrote:
> > template<class T> void hash_combine( size_t& seed, T const& v )
> 
> In principle it sounds like an improvement, but what about the paper "Types
> Don't Know #?"
> (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3980.html)
> 
> The paper shows empirical evidence that hash_combine has poor collision
> properties when composing hash functions.

...

> What happens with hash_append from the paper?

As you well know, what happens with hash_append from the paper is
that it has been sitting in https://github.com/pdimov/hash2 for years now
while I was promising to finish the library and submit it to Boost. I'm still doing
that. (Promising, I mean.)