Module voiceleading 

Two-voice voice-leading classification and parallel-interval checks. Two-voice voice-leading checks, a port of music21’s VoiceLeadingQuartet.

A quartet is two consecutive notes in an upper voice and two in a lower voice. It classifies how the voices move between them and finds the parallel and hidden perfect intervals that common-practice counterpoint forbids.

Structs

QuartetOptions

Which quartets iterate_all_voice_leading_quartets gives: music21’s keyword arguments of the same names, with its defaults.

VoiceLeadingQuartet

Two consecutive notes in each of two voices. Voice one is the upper voice.

Enums

MotionType

How two voices move relative to each other.

ParallelRequirement

What a caller may ask of a parallel motion.

Functions

iterate_all_voice_leading_quartets

Every VoiceLeadingQuartet in a stream, generally a score: music21’s iterateAllVoiceLeadingQuartets.

verticality_at

What is sounding or standing in each part at an offset, part by part: music21’s getVerticalityFromObject, asked by offset since a stream here owns its notes and an offset is what says where one is.

verticality_positions_at

verticality_at by position: for each part holding anything at the offset, the part’s index and the positions in Stream::leaves of what it holds there, for a caller that keeps something of its own beside each element.

voice_leading_quartet_positions

Where the four notes of every quartet iterate_all_voice_leading_quartets finds stand in the stream: each quartet as the offset it is found at and the positions in Stream::leaves of its v1n1, v1n2, v2n1 and v2n2, in that order. This is the walk itself, for a caller that keeps something of its own beside each note and wants that back rather than a copy of the pitch; the offset is what music21’s reverse walks backwards by, since a voice held through has its notes start earlier.