def blend_chords(pc1, pc2):
spec1 = get_chord_spec(pc1)
spec2 = get_chord_spec(pc2)
generic_space = set.intersection(spec1, spec2)
path1 = get_generalization_path(spec1, generic_space)
path2 = get_generalization_path(spec2, generic_space)
solutions = []
for i, _ in enumerate(path1):
for j, _ in enumerate(path2):
colimit = set.union(generalized(spec1, path1, i),
generalized(spec2, path2, j))
deduced = Chord.classify_uniquely(
pitch_class(axiom) for axiom in colimit
if type(axiom) is AbsNote)
blendoid = {
*deduced, *(pitch_class(axiom + deduced.root)
for axiom in colimit if type(axiom) is RelNote)
}
if check_for_consistency(blendoid):
# TODO: account for deviations from priority ordering
cost = max(i, j)**2 + min(i, j)
solutions.append((blendoid, cost))
return min(solutions, key=itemgetter(1))[0]
def get_chord_spec(notes):
chord = Chord.classify_uniquely(notes)
return {
*map(AbsNote, chord),
*map(RelNote, relative_intervals(chord, chord.root))
}
