[R-pkg-devel] Windows specific compiler for CUDA builds

Thu, Mar 16, 2017 10:48 AM

Thanks Duncan,

You say there aren't a lot of people that no how to do that.  Do you know
of anyone who would?  I assume Dirk would be a likely person given the use
of Rtools with Rcpp.  I am happy to try and work at this as I have a vested
interest in getting CUDA packages to become functional on Windows systems
but I need somewhere to begin.  Basically I'm just looking how to switch
out the MinGW g++ with the VS cl compiler.  On a Linux system I can create
a .R/Makevars file to switch the CXX variable but I don't know how on
Windows.

Charles

On Thu, Mar 16, 2017 at 10:41 AM, Duncan Murdoch <murdoch.duncan at gmail.com>
wrote:

On 16/03/2017 11:00 AM, Charles Determan wrote:

Greetings,

Not sure if this should be on the Rcpp list but it isn't strictly related
to Rcpp but to package building involving Rcpp so I am posting it here.

I am often working on GPU packages that use either OpenCL or CUDA.  OpenCL
is nice because it doesn't require a special additional compiler and I can
build it across platforms with relative ease.  With CUDA, it requires the
'nvcc' compiler.  This is where my problem comes in.  On Windows the
'nvcc'
requires the use of the 'cl' compiler within Visual Studio and the
resulting object files, AFAIK, cannot be linked to object files created by
g++ (via Rtools).  Everything works great on Linux (where the same
compiler
is used for everything) but on a Windows system this is causing a lot of
headaches.

So, at the moment, my conclusion is that it is simply not possible to
build
a CUDA package that can be installed on a Windows system.  To my
knowledge,
no CUDA based R package has a Windows installation functional (please
state
otherwise if I am wrong).

My only thought would be if it would be possible to have the Windows build
use 'cl' for the entire build process.  Perhaps that would allow all the
files to be linked together and create the necessary shared object at the
end?  Obviously the preference is to use Rtools but until NVIDIA updates
their special compiler to support MinGW tools I don't think that is
possible.

In principle it should be possible to use cl.  In practice, it will
require someone to work out the details of doing it and to maintain it (by
testing R-devel regularly to make sure changes there don't cause trouble
for it).  There aren't a lot of people who know how to do that (e.g. I
don't).  If you are willing to volunteer to do this (or can recruit someone
to do it), go ahead.  Assuming you do a good job, we can put your patches
into the base code.

Duncan Murdoch

[R-pkg-devel] Windows specific compiler for CUDA builds

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