Hi,

I saw in the documentation that SMID implementation for the log-function were already done in EIGEN 3.

I tested the function ei_log from EIGEN but saw no difference in comparision with the std::log. Did I call the wrong function ?

Thanks

ei_log just calls std::log.

The SIMD implementation is ei_plog. It works on a packet of 4 floats. See in Eigen/src/Core/arch/SSE/MathFunctions.h.

Thanks for the quick answer !

Does it work on double also, since I only use double ?

No, currently only the float version is vectorized.

Ok, thanks !

I have another question : When I call the method log() on an Array/Matrix to compute the log coefficient-wise, is ei_plog used ? If not, what should I do to use ei_plog on an Array/Matrix ?

Thanks

P.S: I tried to read the source code, but since my C++ is very elementary, especially Template, it was not quite clear to me, how did you do it.

It's used as much as possible; falling back to ei_log when it's not possible.