Summary
NegativeVolumeIndex is RTTA's streaming implementation of: Cumulative indicator that changes on lower-volume periods.
Update API
result = rtta.NegativeVolumeIndex().update(close, volume)
The update(...) call consumes one observation using close, volume. advance(...)
uses the same inputs when the caller wants to update state without materializing
a Python return value.
Theory Of Operation
NegativeVolumeIndex combines price, volume, and/or quote information into a streaming microstructure or participation measure. The update path advances only from the latest tick and prior state.
Recurrence
Let \(z_t = (close_t, volume_t)\) denote the observation consumed by one
update(...) call and let \(\theta\) denote constructor parameters such as
window lengths, thresholds, and smoothing constants.
The return value is the current scalar indicator value.
Implementation Notes
The recurrence is implemented in src/rtta/indicator.cpp in class NegativeVolumeIndex.