SparseSuite can't locate blas

[gx001085]

Hello,

I have blas/lapack libraries residing here: /home/myUserName/Libraries/Lapack/lib/ :
libcblas.a liblapack.a librefblas.a libtmglib.a

SuiteSparse returns this error when builidng it (~/Libraries/CMake/cmake-4.0.2-linux-x86_64/bin/cmake -DSUITESPARSE_USE_64BIT_BLAS=ON -DCMAKE_INSTALL_PREFIX=.. ..)

--

-- Looking for 64-BLAS: /home/myUserName/Libraries/Lapack/lib/
CMake Error at /home/myUserName/Libraries/CMake/cmake-4.0.2-linux-x86_64/share/cmake-4.0/Modules/FindPackageHandleStandardArgs.cmake:227 (message):
Could NOT find BLAS (missing: BLAS_LIBRARIES)

The blas library is there (libcblas.a), so why can't SuiteSparse find it?

[DrTimothyAldenDavis]

SuiteSparse is using the cmake command, find_package ( BLAS ...) . So you'll need to look at the cmake documentation. It probably doesn't recognize libcblas.a as a BLAS library. Also, it looks like you're setting BLA_VENDOR to a folder, but that's not how the FindBLAS.cmake script works. It's not a directory or folder, it's the name of the BLAS library; see https://cmake.org/cmake/help/latest/module/FindBLAS.html#blas-lapack-vendors .

[gx001085]

Thank you for the reply and explanation of what BLA_VENDOR means.
I am surprised however that it is even an issue, since I am using the office lapack/blass distribution and compilation from https://www.netlib.org/lapack/

[mmuetzel]

SuiteSparse doesn't use cblas. That is a C wrapper library around BLAS.

SuiteSparse should be able to build with any BLAS compatible library (that is supported by CMake). For the reference implementation, the library name is libblas by default. (Note that this name does not contain a "c".)
It looks like you configured LAPACK to use the name librefblas instead or you renamed that library manually after it was built.
In that case, CMake probably can't detect it automatically. Try building SuiteSparse after you configured it with -DBLAS_LIBRARIES="/home/myUserName/Libraries/Lapack/lib/librefblas.a".

Does that make a difference?

[mmuetzel]

Also, if you haven't done so yet, add -DCMAKE_PREFIX_PATH="/home/myUserName/Libraries/Lapack" to your configuration flags. Otherwise, CMake might not know where to look for the LAPACK library either...

[gx001085]

Wow, that made a difference. I also had to add -DLAPACK_LIBRARIES configuration option. THANK YOU!!!
So that worked fine, but now a I hit a snug with GMP library - I suppose you are recommending https://github.com/clouren/SPEX, correct?

[mmuetzel]

Not sure what you mean by recommending SPEX for GMP.
That repository is "upstream" for SuiteSparse afaict.

To build either the upstream library or the one bundled in SuiteSparse, you'd need:

• the GMP library: https://gmplib.org/
• and the MPFR library: https://www.mpfr.org/

[gx001085]

Makes sense! Thank you