On 28.03.2014 22:38, Olivier Grisel wrote: > 2014-03-28 22:18 GMT+01:00 Nathaniel Smith <n...@pobox.com>: >> I thought OpenBLAS is usually used with reference lapack? > > I am no longer sure myself. Debian & thus Ubuntu seem to be only > packaging the BLAS part of OpenBLAS for the libblas.so symlink and > uses the reference implementation of lapack for the liblapack.so > symlink.
You can link the reference lapack with any library providing a BLAS compatible API/ABI. ATLAS and OpenBlas are ABI compatible with reference BLAS which allows replacing the library via LD_PRELOAD or debian alternatives without recompiling. Both ATLAS and OpenBlas provide a subset of optimized lapack functions, but they are optional. On Debian/Ubuntu you can install ATLAS lapack but then you are also forced to use ATLAS blas. I am not familiar with how relevant the optimized parts of lapack for the general use case. > > I observed a sparse leastsqr bug when linking scipy against the full > OpenBLAS under OSX that I could not reproduce under with the openblas > + lapack combo shipped Ubuntu so there might be a difference. But that > could also be caused by a version / platform discrepancy between my > two setups. > what kind of a bug? wrong result or crash? Which target did openblas use when compiling on macos? or was it a dynamic build? (see the name of the built static library) The adaptive nature of OpenBLAS can make reproducing issues tricky, I don't think there is a way to force it to use a certain kernel at runtime besides recompiling for a different target. If you have a testcase I'd be interested in it, as I'm trying to get openblas into a decent shape for ubuntu 14.04. _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
