[R-SIG-Mac] OpenMP on CRAN

BATES Timothy t|m@b@te@ @end|ng |rom ed@@c@uk
Thu Apr 2 15:01:18 CEST 2020

Moving to a compiler that drops support for OpenMP seems a sad choice, especially now we’ve all climbed the learning curve of the non-Apple compiler (the real barrier was lack of a pkg installer and that’s done now).

Losing OpenMP for the CRAN version of OpenMx/umx (our SEM packages) would be a big loss for users (for whom the CRAN version now supports OpenMP giving them a 2-12x speed up). In general, R on Mac is made more viable by having OpenMP

Re Brian’s points, I’d say that the distribution problem is crucial: Packages not on CRAN have dramatically diminished accessibility/useage.

Second, a great range of compute-intensive problems are amenable to division amongst cores, including nearly all models that take more than a nominal amount of time to run: So simulations, CIs, bootstrapping, nearly everything in genetics all speeds up.

I’d say especially on desktop/laptop. The big advantage of multi blade systems requires snowfall-type solutions, but desktops profit automatically from their multi-core structure and don;’t have multiple processors (except graphics, which no-one seems to be exploiting on CRAN-style R), so OpenMP is their one trick. I’d hope not to lose it.

Best, t

> On 2 Apr 2020, at 05:18, Prof Brian Ripley <ripley using stats.ox.ac.uk> wrote:
> On 01/04/2020 22:02, Simon Urbanek wrote:
>> JJB,
>> 1. correct, there was too much trouble in this. But please feel free to start a new thread about this here if you have strong opinions.
> Also note that it is possible (and not hard) to install packages from source with an OpenMP-supporting compiler, and how to do so is in the R-admin manual.  The problems come in distributing them.
> The benefits of OpenMP are often overestimated, especially on desktop/laptop level hardware.  But it is available for the small (tiny?) proportion of users who need it.
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