@Erik Schnetter reports that to have NSIMD actually use SIMD instructions one needs to set preprocessor defines (see https://github.com/agenium-scale/nsimd/blob/master/doc/markdown/defines.md).

Pull request is here: https://github.com/EinsteinToolkit/ExternalLibraries-NSIMD/pull/1

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2765/nsimd-is-not-actually-build-with-simd-code