Definition: (1) A vertex of a directed graph with no incoming edges. More formally, a vertex with in-degree 0. (2) The vertex from which an edge of a directed graph leaves.

See also sink, supersource, flow network, critical path problem, multi-commodity flow, (2) target.

Note: Conceptually, an origin of whatever is directed in the graph. In UML, a producer of data in a design.

(2) That is, an edge goes from the source to the target.

Author: PEB

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Entry modified 17 December 2004.
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Cite this as:
Paul E. Black, "source", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed. 17 December 2004. (accessed TODAY) Available from: