Graph propagated information can consist of a node's complete state, i.e., the computation result of the involved node. In such cases, the node's previous output is then ignored. Another method involves "delta propagation" i.e. "incremental change propagation". In this case, information is proliferated along a graph's "edges," which consist only of "delta"s describing how the previous node was changed. This approach is especially important when "nodes" hold large amounts of "state data", which would otherwise be expensive to recompute from scratch.