numerator relationship matrix https://www.r-bloggers.com/setup-up-the-inverse-of-additive-relationship-matrix-in-r/ Philippe Rocca-Serra adapted from: https://jvanderw.une.edu.au/Genetic_properties_of_the_animal_model.pdf and from: Henderson, C.R. 1976. A simple method for computing the inverse of a numerator relationship matrix used in prediction of breeding values. Biometrics 32:69-83. https://doi.org/10.2307/2529339 https://rdrr.io/cran/sommer/man/A.mat.html A matrix the numerator relationship matrix is the matrix of *expected* additive genetic relationships between individuals. This matrix was originally used by Henderson (Henderson, C.R. 1976. A simple method for computing the inverse of a numerator relationship matrix used in prediction of breeding values. Biometrics 32:69-83.) to account for covariances between random effects, and therefore to use information from relatives in estimation of breeding value. Among the properties of the NRM matrix (also known as the A matrix), it is symmetric, the diagonal value correspond to 1+ the inbreeding coefficient for an individual. NRM matrix ready for release