Figure 2

The BASILISK dynamic Bayesian network: The network shown represents an amino acid with two χ angles, such as for example histidine. In this case, the DBN consists of four slices: two slices for the ϕ, ψ angles, followed by two slices for the χ angles. Sampling a set of χ angles is done as follows. First, the values of the input nodes (top row) are filled with bookkeeping indices that determine both the amino acid type (for example histidine) and the labels of the angles (for histidine, ϕ, ψ followed by χ₁ and χ₂). In the next step, the hidden node values (middle row, discrete nodes) are sampled conditioned upon the observed nodes. These observed nodes always include the index nodes (top row, discrete nodes), and optionally also the ϕ, ψ nodes (first two nodes in the bottom row) if the sampling is conditioned on the backbone. Finally, a set of χ angles is drawn from the von Mises nodes (bottom row), whose parameters are specified by the sampled values of the hidden nodes.