idea: https://github.com/loic-yengo/REML-with-sparse-relationship-matrices/blob/main/sparseREML_v0.6_toshare.R This just focuses on one level of relatedness
idea: https://github.com/loic-yengo/REML-with-sparse-relationship-matrices/blob/main/sparseREML_v0.6_toshare.R
This just focuses on one level of relatedness