Bug#948954: libblis2-pthread: undefined symbol: openblas_set_num_threads

[Drew Parsons]

Package: libblis2-pthread
Followup-For: Bug #948954

Hi Jörg, your error refers to openblas, which is a separate BLAS
implementation from blis.  The implementations are compatible, but
only when built against libblas.so using -lblas, i.e. when using the
common BLAS ABI.

The appearance of the openblas symbol suggests that your applications
were built using -lopenblas instead of -lblas, enabling some
openblas-specific symbols to be called in.

You've got two options,

1) rebuild your binaries (and to protect from the same problem in the
   future, ensure they link strictly against -lblas)

2) install OpenBLAS instead of BLIS (e.g. install libopenblas-pthread-dev)
   Together with that you'd probably want to check that the blas
   alternatives match, running both 
     sudo update-alternatives --config libblas.so-x86_64-linux-gnu`
   *and*
     sudo update-alternatives --config libblas.so.3-x86_64-linux-gnu