[R-SIG-Mac] Change to BLAS (from default to Apple vecLib) doesn't report in sessionInfo()

[Clement Kent]

I experienced the same thing. I switched to libRblas.vecLib.dylib and got
the remarkable speedup
in matrix multiplication, but sessionInfo doersn't show that I'm using it.
MacBook Pro (14-inch, 2021)

sessionInfo()
R version 4.2.2 (2022-10-31)
Platform: aarch64-apple-darwin20 (64-bit)
Running under: macOS Monterey 12.6.2

Matrix products: default
LAPACK:
/Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/lib/libRlapack.dylib

Random number generation:
 RNG:     Mersenne-Twister
 Normal:  Inversion
 Sample:  Rounding

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] datasets  parallel  utils     stats     graphics  grDevices methods
base

other attached packages:
[1] showtext_0.9-5    showtextdb_3.0    sysfonts_0.8.8    data.table_1.14.6
nlme_3.1-160      MASS_7.3-58.1

loaded via a namespace (and not attached):
[1] compiler_4.2.2  tools_4.2.2     grid_4.2.2      lattice_0.20-45
R 4.2.2 GUI 1.79 Big Sur ARM build (8160)

On Mon, Jan 9, 2023 at 5:25 PM David Novgorodsky <
david.novgorodsky using gmail.com> wrote:

> Hi all,
>
> First post, and my apologies if this was addressed already elsewhere, but
> did not seem so to me. This post is (I think) purely about the
> behavior of sessionInfo()
> after I switch the BLAS to Apple's Accelerate vecLib.
>
> I installed R 4.2.2 on macOS Monterey 12.6.2 (with an M1 chip)
> successfully. I run sessionInfo() with the following result:
>
> R version 4.2.2 (2022-10-31)
>
> Platform: aarch64-apple-darwin20 (64-bit)
>
> Running under: macOS Monterey 12.6.2
>
>
>
> Matrix products: default
>
> BLAS:
>
> /Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/lib/libRblas.0.dylib
>
> LAPACK:
>
> /Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/lib/libRlapack.dylib
>
>
>
> locale:
>
> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
>
>
>
> attached base packages:
>
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
>
>
> loaded via a namespace (and not attached):
>
> [1] compiler_4.2.2
>
> And then I run a small piece of test code (taken from somewhere, sorry,
> can't recall where):
>
> N <- 20000
> M <- 2000
> X <- matrix(rnorm(N*M),N)
> system.time(crossprod(X))
>
> with result
>
> > system.time(crossprod(X))
> user  system  elapsed
> 49.471  0.082  49.553
>
> Then I change my BLAS (using the vecLib supplied as part of the R
> installation package), e.g., in the Terminal app:
>
> cd /Library/Frameworks/R.framework/Resources/lib
> ln -sf libRblas.vecLib.dylib libRblas.dylib
>
> Afterwards, I restart R. Re-running the small piece of test code above
> yields
>
> > system.time(crossprod(X))
> user  system  elapsed
> 0.339  0.015  0.197
>
> which suggests to me that the switch to vecLib did, indeed, succeed.
>
> However, sessionInfo() does something unexpected -- it no longer reports
> anything for the BLAS row:
>
> R version 4.2.2 (2022-10-31)
>
> Platform: aarch64-apple-darwin20 (64-bit)
>
> Running under: macOS Monterey 12.6.2
>
>
>
> Matrix products: default
>
> LAPACK:
>
> /Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/lib/libRlapack.dylib
>
>
>
> locale:
>
> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
>
>
>
> attached base packages:
>
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
>
>
> loaded via a namespace (and not attached):
>
> [1] compiler_4.2.2
>
> Anyone have any leads on whether a) this is a problem, and b) how to fix it
> (if so)? Seems this has been the case at least for a couple of years, at
> least based on an only tangentially related past thread (link here
> <https://stat.ethz.ch/pipermail/r-sig-mac/2020-November/013794.html>)
> where
> the responder implicitly shows the same thing -- faster matrix
> multiplication, but not reporting of BLAS in sessionInfo().
>
> Thanks,
> David
>
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>
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