openfermion.measurements.pair_within_simultaneously

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Generates simultaneous pairings between four-element combinations

openfermion.measurements.pair_within_simultaneously(
    labels: list
) -> tuple

A pairing of a list is a set of pairs of list elements. E.g. a pairing of

labels = [1, 2, 3, 4, 5, 6, 7, 8]

could be

[(1, 2), (3, 4), (5, 6), (7, 8)]

(Note that we insist each element only appears in a pairing once; the following is not a pairing:

[(1, 1), (2, 2), (3, 4), (5, 6), (7, 8)]

This function generates a set of pairings such that for every four elements (i,j,k,l) in 'labels', there exists one pairing containing both (i,j) and (k,l)