[R-pkg-devel] using portable simd instructions

[Dirk Eddelbuettel]

On 27 March 2024 at 08:48, jesse koops wrote:
| Thank you, I was not aware of the easy way to search CRAN. I looked at
| rcppsimdjson of course, but couldn't figure it out since it is done in
| the simdjson library if interpret it correclty, not within the R
| ecosystem and I didn't know how that would change things. Writing R
| extensions assumes a lot of  prior knowledge so I will have to work my
| way up to there first.

I think I have (at least) one other package doing something like this _in the
library layer too_ as suggested by Tomas, namely crc32c as used by digest.
You could study how crc32c [0] does this for x86_64 and arm64 to get hardware
optimization. (This may be more specific cpu hardware optimization but at
least the library and cmake files are small.)

I decided as a teenager that assembler wasn't for me and haven't looked back,
but I happily take advantage of it when bundled well. So strong second for
the recommendation by Tomas to rely on this being done in an external and
tested library.

(Another interesting one there is highway [1]. Just packaging that would
likely be an excellent contribution.)

Dirk

[0] repo: https://github.com/google/crc32c
[1] repo: https://github.com/google/highway
    docs: https://google.github.io/highway/en/master/


| 
| Op di 26 mrt 2024 om 15:41 schreef Dirk Eddelbuettel <edd using debian.org>:
| >
| >
| > On 26 March 2024 at 10:53, jesse koops wrote:
| > | How can I make this portable and CRAN-acceptable?
| >
| > But writing (or borrowing ?) some hardware detection via either configure /
| > autoconf or cmake. This is no different than other tasks decided at install-time.
| >
| > Start with 'Writing R Extensions', as always, and work your way up from
| > there. And if memory serves there are already a few other packages with SIMD
| > at CRAN so you can also try to take advantage of the search for a 'token'
| > (here: 'SIMD') at the (unofficial) CRAN mirror at GitHub:
| >
| >    https://github.com/search?q=org%3Acran%20SIMD&type=code
| >
| > Hth, Dirk
| >
| > --
| > dirk.eddelbuettel.com | @eddelbuettel | edd using debian.org

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dirk.eddelbuettel.com | @eddelbuettel | edd using debian.org