libtcspc.ArrayEventType¶

class libtcspc.ArrayEventType(element_type, count)[source]¶

Bases: EventType

Event holding a fixed-size array of elements of another event type.

The corresponding C++ event is std::array<T, N>, where T is the element type and N is the (compile-time) element count. Use this for events that group a fixed number of structured elements, such as a pair of detections (DetectionPairEvent), or for future N-fold correlation.

Parameters:

element_type (EventType) – The event type of the array elements. It must support value construction (see EventType.value()).
count (int) – The number of elements in the array. Must be at least 1.

Notes

A value of this type is constructed with the single field elements, given as a sequence of exactly count EventInstance values of element_type:

ArrayEventType(DetectionEvent(nt), 2).value(elements=[start, stop])

When delivered to a Python sink (or read back), elements is a tuple of EventInstance values of element_type. For convenience, an EventInstance of this type also supports len(...) and indexing (inst[i]), which return the elements directly.

Whether values can be embedded in compiled code (and used with Prepend/Append) and whether they are hashable follow from the element type: an array of scalar-only elements is embeddable and hashable; an array of bucket-carrying elements is neither.

Constructing and inspecting individual event values from Python is intended for debugging and learning only and is extremely slow; production graphs process events in compiled C++ and exchange bulk data via buckets.