In mathematics, particularly graph theory, and computer science, a directed acyclic graph is a directed graph with no directed cycles. That is, it consists of vertices and edges, with each edge directed from one vertex to another, such that following those directions will never form a closed loop.

What is meant by directed acyclic graph?

A directed acyclic graph is a directed graph that has no cycles. A vertex v of a directed graph is said to be reachable from another vertex u when there exists a path that starts at u and ends at v. As a special case, every vertex is considered to be reachable from itself (by a path with zero edges).

What are DAGs used for?

DAGs are used to encode researchers' a priori assumptions about the relationships between and among variables in causal structures. DAGs contain directed edges (arrows), linking nodes (variables), and their paths.