New in version 2.0.
Calculate melodic chromatic interval from pitch_carrier_1 to pitch_carrier_2:
abjad> pitchtools.calculate_melodic_chromatic_interval_from_pitch_carrier_to_pitch_carrier(pitchtools.NamedChromaticPitch(-2), pitchtools.NamedChromaticPitch(12))
MelodicChromaticInterval(+14)
Return melodic chromatic interval.