Flow chart of the MODA algorithm. This schematic representation of MODA reveals two distinct steps (the choice of successors and the integration of τ), each of which involves a loop over all grid points (or cells). The algorithm is completely described by this chart, and all specific decisions that are not included in the figure (e.g., how to pick the initial r and how much to successively increase it afterwards) are parametrizations that depend on the underlying implementation (i.e., grid-based or tree-based).