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Re: OpenBlas Pthread issue with R

On 30 April 2020 at 18:16, Sébastien Villemot wrote:
| Le jeudi 30 avril 2020 à 10:43 -0500, Dirk Eddelbuettel a écrit :
| > On the r-sig-debian list (hosted by the R Project for users of R on Debian
| > and Ubuntu) someone pointed out that R hangs on simple calls into OpenBLAS
| > Pthread, i.e. /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3
| > 
| > To witness, just launch R and issue the   example(solve)   which spends two
| > lines setting a helper Hilbert function and input data with it and then hangs
| > on the actual call to solve() (see below for full example)
| > 
| > Is this a known issue? Do we need to set some OpenMP env vars to limit thread
| > use?
| The problem was there in the past but was solved. I don’t know why it
| is happening again. See
| https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=739331
| Also note that (in unstable/testing) there are now OpenMP and single-
| threaded flavours of OpenBLAS (in packages libopenblas0-openmp and
| libopenblas0-serial). As a workaround, you can try to install one of
| these two (and adjust the BLAS alternatives accordingly).

Switching to libopenblas0-openmp works but one needs to uninstall
libopenblas0-pthread (or else fiddle with the alternatives priority).


http://dirk.eddelbuettel.com | @eddelbuettel | edd@debian.org

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