Download Random Effects in AD Model Builder - available
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1.1.2 Computational basis of admb-re • Hyper-parameters (variance components, etc.) estimated by maximum likelihood. • Marginal likelihood evaluated by the Laplace approximation, (adaptive) importance sampling or Gauss-Hermite integration. • Exact derivatives calculated using Automatic Differentiation. • Sampling from the Bayesian posterior using mcmc (Metropolis-Hastings algorithm). • Most of the features of ordinary admb (matrix arithmetic and standard errors, etc.) are available. • Sparse matrix libraries, useful for Markov random fields and crossed random effects, are available. 1.1.3 The strengths of admb-re • Flexibility: You can fit a large variety of models within a single framework. • Convenience: Computational details are transparent. Your only responsibility is to formulate the log-likelihood. • Computational efficiency: admb-re is up to 50 times faster than Winbugs. • Robustness: With exact derivatives, you can fit highly nonlinear models. • Convergence diagnostic: The gradient of the likelihood function provides a clear convergence diagnostic. 1.1.4 Program interface • Model formulation: You fill in a C++-based template using your favorite text editor. • Compilation: You turn your model into an executable program using a C++ compiler (which you need to install separately). • Platforms: Windows, Linux and Mac. 1.1.5 How to obtain admb-re admb-re is a module for admb. Both can be obtained from admb-project.org. 1-3