reduce_merge_histograms

reduce_merge_histograms(grouped)

Reduce grouped probability dicts by averaging across groups.

Equivalent to the VQA _average_probabilities logic: for each base_key, collects all probability dicts, unions all bitstrings, and averages the probability values. Used by TrotterSpecStage in measurement pipelines to merge probability histograms across Hamiltonian samples.

Example:

>>> grouped = {(('circ', 0),): [{'00': 0.6, '11': 0.4}, {'00': 0.8, '11': 0.2}]}
>>> reduce_merge_histograms(grouped)
{(('circ', 0),): {'00': 0.7, '11': 0.3}}

Return type:

dict[Any, Any]