The HUGIN API is thread-safe and can be used in multithreaded applications. You may find more information on multiprocessing and multitreaded applications in the HUGIN (C) API Reference Manual section 1.8.
The first part of section 1.8 reads:
The HUGIN API can be used safely in a multithreaded application. The major obstacle to thread-safety is shared data—for example, global variables. The only global variable in the HUGIN API is the error code variable. When the HUGIN API is used in a multithreaded application, an error code variable is maintained for each thread.
The section also includes some advice on the use og HUGIN in multithreaded applications:
The most common usage of the HUGIN API in a multithreaded application will most likely be to have one or more dedicated threads to process their own domains (e.g., insert and propagate evidence, and retrieve new beliefs). In this scenario, there is no need (and is also unnecessarily inefficient) to protect each node or domain by a mutex (mutual exclusion) variable, since only one thread has access to the domain. However, if there is a need for two threads to access a common domain, a mutex must be explicitly used.
