Bidirectional

Bidirectional describes a property of systems, signals, or relations that operate or extend in two directions. It implies reciprocity or two-way interaction, in contrast to unidirectional systems that move only in a single direction.

In communications and networks, bidirectional denotes channels that support two-way data transmission between endpoints. Examples include telephone lines, chat protocols, and many network links that allow simultaneous or alternating upstream and downstream communication.

In computing, bidirectional appears with text, data, and synchronization. Bidirectional text support enables display and input of scripts that mix left-to-right and right-to-left writing, following standards such as the Unicode Bidirectional Algorithm.

In mathematics and logic, bidirectional can describe a relation or mapping that is invertible or symmetric. A bidirectional mapping has a reverse operation such that applying forward and then reverse retrieves the original input.

In algorithms and AI, bidirectional search explores from both the start and the goal to reduce search space, improving efficiency in suitable graphs, as in bidirectional Dijkstra or bidirectional A*.

In physics and computer graphics, bidirectional concepts appear in models such as the Bidirectional Reflectance Distribution Function, which describes how light reflects off a surface for both incident and outgoing directions.