With eigen3 including upstream's patch mentioned by Philipp [1], opensurgsim now builds and passes all 12 tests on ppc64el, but fails 1 test on amd64 and 3 tests on arm64. I don't know if more work is needed in the eigen3 patch or in opensurgsim. [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=835411#36