R detection of Blas version

I think you cannot. R will be built against the BLAS interface, and R itself does not which package supplies the actual library.

You can only look at ldd output. On my server, this points to Atlas

edd@max:~$ ldd /usr/lib/R/bin/exec/R    linux-vdso.so.1 =>  (0x00007fffc8ddb000)    libR.so => /usr/lib/libR.so (0x00007f8be940c000)    libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f8be91ef000)    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f8be8e4d000)    libblas.so.3gf => /usr/lib/atlas-base/atlas/libblas.so.3gf (0x00007f8be88e4000)    libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f8be8660000)    libreadline.so.6 => /lib/libreadline.so.6 (0x00007f8be841d000)    libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007f8be81e1000)    liblzma.so.2 => /usr/lib/liblzma.so.2 (0x00007f8be7fbf000)    libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f8be7da6000)    librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f8be7b9e000)    libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f8be799a000)    libgomp.so.1 => /usr/lib/x86_64-linux-gnu/libgomp.so.1 (0x00007f8be778b000)    /lib64/ld-linux-x86-64.so.2 (0x00007f8be99a5000)    libgfortran.so.3 => /usr/lib/x86_64-linux-gnu/libgfortran.so.3 (0x00007f8be7475000)    libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f8be725f000)    libtinfo.so.5 => /lib/libtinfo.so.5 (0x00007f8be7037000)    libquadmath.so.0 => /usr/lib/x86_64-linux-gnu/libquadmath.so.0 (0x00007f8be6e01000)edd@max:~$ 

which makes sense as this BLAS-providing package gets the highest priority per the Debian packaging.

Edit, some nine years later: R, which always grows in capabilities, now reports this (even pretty-printed) in sessionInfo(). On my machine (R 4.1.1, Ubuntu 21.04) it says just that too:

> sessionInfo()R version 4.1.1 (2021-08-10)Platform: x86_64-pc-linux-gnu (64-bit)Running under: Ubuntu 21.04Matrix products: defaultBLAS:   /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblasp-r0.3.13.so[...]

You can also access those two paths directly:

> si <- sessionInfo()> si$BLAS[1] "/usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3"> si$LAPACK[1] "/usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblasp-r0.3.13.so"> 

In R, type:

sessionInfo()

which should give you among other things the BLAS used as well.

For example, on my machine I get:

Platform: x86_64-pc-linux-gnu (64-bit)Running under: Ubuntu 18.04.3 LTSMatrix products: defaultBLAS:   /usr/lib/x86_64-linux-gnu/openblas/libblas.so.3LAPACK: /usr/lib/x86_64-linux-gnu/libopenblasp-r0.2.20.solocale: [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C               LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8     LC_MONETARY=en_US.UTF-8    [6] LC_MESSAGES=en_US.UTF-8    LC_PAPER=en_US.UTF-8       LC_NAME=C                  LC_ADDRESS=C               LC_TELEPHONE=C            [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       attached base packages:[1] stats     graphics  grDevices utils     datasets  methods   base     loaded via a namespace (and not attached):[1] compiler_3.6.1    Matrix_1.2-17     tools_3.6.1       Rcpp_1.0.2        grid_3.6.1        data.table_1.12.2 packrat_0.5.0     lattice_0.20-38  [9] stm_1.3.3        

This solution works if its enough for you to know at which path the BLAS library can be found. For example, I use this solution to decide whether to load the package libraries for the "normal" R version or the OpenBLAS version.

Of course, you can not know where other people store their libraries, so for use in a package or shared code it is not suitable. But for own maintenance it can be used:

extSoftVersion()["BLAS"]## [1] "/the/path/to/your/libblas.so"