After more than three years of efforts, Eigen 3.3 has been released today, on November 10, 2016.
Since Eigen 3.2, the 3.3 version leverage numerous major novel features and improvements that are summarized in the dedicated 3.3 release page [1].
Those include, a novel evaluation mechanism [2] of expressions, support for AVX, FMA, AVX512, VSX and ZVector vector instructions, unaligned vectorization, nvcc/CUDA, more OpenMP parallelism [3], a fast divide and conquer SVD algorithm [4], a CompleteOrthogonalDecomposition class for fast minimal norm solving [5], a LS-CG solver [6], a fast reciprocal condition number estimators in LU and Cholesky factorizations, LU::transpose()/adjoint() API [7], support for inplace decompositions [8], support for matrix-free iterative solvers [9], new array functions [10], support for any BLAS/LAPACK libraries as backend [11], improved support for mixing scalar types [12], eigenvectors in GeneralizedEigenSolver, a complete rewrite of LinSpaced [13], a non officially supported but massively used Tensor module with CUDA and OpenCL support [14], and more [1].