Comparison of parameter estimates and computation time for SAS NLMIXED and ADMB-RE for the 2-RE model with correlation from Booth et al. (2005). Two different starting values (Init) are considered for each program.

Init ADMB-RE SAS Init ADMB-RE SAS b 0 -1.32058 -1.3205 0 -1.32058 -1.3207 b 0 0.884235 0.8842 0 0.884235 0.8842 b 0 -0.928159 -0.9282 0 -0.928159 -0.9282 b 0 0.336107 0.3361 0 0.336107 0.3362 b 0 0.472141 0.4721 0 0.472141 0.4722 b 0 -0.268296 -0.2683 0 -0.268296 -0.2685 log(sigma_1) 0 -0.760283630236 -0.7603 0 -0.760283630236 -0.7603 log(sigma_2) -1 -4.85981940818 -4.8652 -1 -4.85981940818 -4.9627 rho -0.8 -0.998999998287 -1 0.8 -0.998999998287 -1 log(alpha) 0 2.00718090809 2.00693485089309 0 2.00718090809 2.00693485089309 loglik 0 -624.418 624.417657 0 -624.418 624.417665 Time (sec) 40 145 40 172