# Armadillo eig_sym() for extracting eigenvalues. Is it parallel at all? [closed]

After wasting 3 days with scalapack, I gave up and moved to Armadillo, considering it uses lapack underneath its beatiful and easy interface.

I would like to calculate the eigen values and eigen vectors of a non-sparse Hermitian matrix. This is very easily done with Armadillo with like 4 lines of code with the function eig_sym().

My question is: Is this function parallelized? How can I parallelize it?

If not, is there any alternative that is not as crazy as lapackand supports parallelization?

BTW: I'm more than happy to implement an algorithm for splitting the matrix into submatrices with Armadillo to get the eigenvalues. Whatever works and doesn't make me spends 2 weeks to get my first set of eigenvalues.

I'm using debian 7 and Armadillo 3 is available in the repos, just in case I have to modify stuff in it (noticed that could be a necessity from reading other posts).

## closed as off-topic by Wolfgang Bangerth, Christian Clason, Paul♦Apr 6 '15 at 20:40

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• I think this is a question best asked on the Armadillo mailing lists or forums. – Wolfgang Bangerth Apr 4 '15 at 11:01
• @WolfgangBangerth Thanks for the suggestions. I'll do that too. – The Quantum Physicist Apr 4 '15 at 11:04
• To make eig_sym() run in parallel, link with OpenBLAS or Intel MKL instead of standard BLAS. See the Armadillo FAQ page for more information. – mtall Aug 4 '15 at 16:17