Slava Pestov wrote:
> Hi Phil,
> 
> Looks like my latest coalescing changes broke a few things in the
> build reports, but I'm working through those... however I noticed that
> performance on benchmark.dawes improved even more. It went from 229 ms
> in the May 31st build, to 160 ms two weeks ago, and now its running at
> 105ms. This is on my Core 2 Duo Mac Book Pro.
> 

Excellent work - that's a v impressive improvement.

> [ ... ]
> If I recall correctly, I based this benchmark on the inner loop of
> some bloom filter code you posted at one point. It would be
> interesting to see if the original code got faster too.
> 

I'm really looking forward to digging into the new compiler.
The problem I was trying to solve was basically doing indices for a set
of inputs:

http://www.phildawes.net/blog/2008/09/10/searching-arrays-in-x86-assembler-with-a-bloom-filter/

" I have a set of 32bit integers, and I want to search a large unsorted
32bit array accumulating the array indices of values matching those from
the set. To solve this in factor I've been putting the input set in a
hashtable and then sequentially looking up each element from the array,
which algorithmically is pretty optimal O(n+m) but the ever present
constant is pretty high. This takes about 4 seconds on a processor
pegged at 800mhz for a 48MB array."

I ended up using a simple bloom filter and some assembler to find
approximate matches and then filtering in factor afterwards, for a total
of 100ms or so at 800mhz.

http://phildawes.net/blog/2008/09/12/searching-arrays-in-x86-assembler-with-a-bloom-filter-pt-3/

It'd be cool to try a pure factor implementation of the same approach so
I'll try this again soon.

Cheers,

Phil


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