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

[David Novgorodsky]

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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