build_Sigma             Build a covariance matrix Sigma
build_Xchi_grad         Build chi using an analytical gradient
build_Xchi_numeric      Build chi via centered finite differences
efficiency_bound        Compute an efficiency lower bound for a given
                        design
exact_design            Convert a Virtual Noise design measure into an
                        exact design
plot_convergence        Plot convergence of the D-optimality criterion
plot_design_weights     Plot design weights over the candidate set
plot_efficiency         Plot efficiency diagnostic
virtual_noise_Dopt      Virtual Noise algorithm for D-optimal design
vndesign_Dopt           Main interface for constructing D-optimal
                        designs using the Virtual Noise algorithm
