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JMMackenzie / IOQP

Impact Ordered Query Processing
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Can we support 32-bit accumulators? #18

Closed JMMackenzie closed 2 years ago

JMMackenzie commented 2 years ago

Need to check whether the fast SIMD blocking will work, or if we need a different method of collecting the top-k.

JMMackenzie commented 2 years ago

Note that this is important for when we allow weighted queries; Currently we only allow i16 as our accumulator type, and this will lead to overflows.

It's better to use u16 as the default and u32 if necessary perhaps.

Unfortunately some of the SIMD intrinsics seem to require signed 16's; I'm not too sure if we can do the same thing with unsigned values.

JMMackenzie commented 2 years ago

@mpetri pointed out: https://doc.rust-lang.org/nightly/core/arch/x86_64/fn._mm256_max_epu16.html

So we should be able to port the current setup to u16's at least.