But the reason I mentioned ICC is that there is much more to SIMD than just linear algebraic operations.
Indeed. I compiled some stuff with ICC, but it did not give me an tangible improvement over the latest GCCs. But for those projects, linear operations were the vast majority.
Its a BLAS library standard API that you are linking to, so the vendor doesn't matter so much (in theory). In practice, the amount of annoyance that you have to go through so that it links correctly can vary a lot. Even MKL did not implement all of BLAS / Lapack and that would lead to some linking errors.
I know that BLAS is a standard API, I switch between BLAS implementations fairly often :). I suspected that Eigen relied on some non-BLAS functions in MKL, since they explicitly state that only MKL works.
I was under the impression that Eigen only works with MKL?
Enables the use of external BLAS level 2 and 3 routines (currently works with Intel MKL only)
Source: http://eigen.tuxfamily.org/dox/TopicUsingIntelMKL.html
But the reason I mentioned ICC is that there is much more to SIMD than just linear algebraic operations.
Indeed. I compiled some stuff with ICC, but it did not give me an tangible improvement over the latest GCCs. But for those projects, linear operations were the vast majority.