Expression of the field covariance for a uniform coordinate grid, i.e. covariance contraction, for all the models implemented in flip. From top to bottom the AB17, AB20, L22, and RC25 models are represented (see Table D.1 for reference). The C23 model is fully equivalent to vv contractions in the AB17, L22, and RC25 models. From left to right are shown the density-density (gg), density-velocity (gv) and velocity-velocity (vv) covariance contractions as a function of transverse (r_⊥) and line-of-sight (r_∥) separations. The gg contraction is multiplied by the squared separation to highlight the BAO pattern.