Next: , Previous: , Up: Top   [Contents][Index]


3 Statistics Storage

Statistics storage holds information on action choice states and cycle types registered by an actor throughout event history. Additionally, statistics storage can hold probability profiles assigned to action choice states.

The function qsmm_actor_create creates statistics storage for an actor. The function qsmm_actor_destroy destroys statistics storage for an actor. The field use_flat_storage of qsmm_actor_desc_s structure passed to the function qsmm_actor_create when creating an actor specifies the type of storage the actor will use—flat storage or map storage.

Storage API functions retrieve or store information on action choice states or cycle types via data structures describing the condition of an action choice state, the condition of a spur type for an action choice state, statistics on a cycle type, and statistics on a spur type for a cycle type. Storage API functions provide means to query the number of spur types supported by storage, to retrieve and store the condition of an action choice state and statistics on a cycle type, to remove information on an action choice state from storage, and to enumerate action choice states and cycle types that have information in storage.

Statistics storage supports setting redirection functions for altering the behavior of storage access operations or intercepting them. Storage redirection functions for obtaining the initial condition of an action choice state, the initial statistics of a cycle type, and the next cycle direction for a cycle type make it possible to generate the probability profile of an action choice state on demand. This approach helps reduce the initial memory footprint of a model and speed up its preparation. QSMM uses those redirection functions internally to implement deferred setting a probability profile for a number of nodes of a multinode model.

Specifying a storage redirection function to intercept updating cycle type statistics makes it possible to organize keeping cycle type statistics for the tail of an event history rather than for the entire event history.


Next: , Previous: , Up: Top   [Contents][Index]