From Eigen

Eigen 3.3-alpha1 has been released on September 4, 2015.

The source archive is at: http://bitbucket.org/eigen/eigen/get/3.3-alpha1.tar.bz2

This alpha version introduces a novel evaluation mechanism of expressions, as well as numerous exciting features such as fast divide and conquer SVD, support for AVX and VSX vector instructions, more OpenMP parallelism, a LS-CG solver, and more. Check the page dedicated on the 3.3 release for a comprehensive review of the novelties and improvements.

As for any alpha and beta release, everybody is invited to test this release on their own basecode and report any compilation issue or performance regression on the bugtracker.

Complete changelog.