 The Hash Table Local Level Set method, introduced in 2012 by Brun, Guittet and Gibou, only computes the level set data in a band around the interface, as in the Narrow Band Level-Set Method, but also only stores the data in that same band.A hash table data structure is used, which provides an formula_17 access to the data.However, the authors conclude that their method, while being easier to implement, performs worse than a quadtree implementation.