A study group on machine learning has been created by the ISO C++
committee. There are interesting discussions about the features and
tools needed for efficiently implement ML algorithms in C++ and I am
sure that mxnet developers will have very interesting things to say.
The goals of the SG are outlined in this paper http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1360r0.pdf
There is a collaborative document here
to which you may contribute.