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Table Of Contents

music21.voiceLeading

music21.voiceLeading.getVerticalSliceFromObject(music21Obj, scoreObjectIsFrom, classFilterList=None)
>>> from music21 import *
>>> c = corpus.parse('bach')
>>> n1 = c.flat.getElementsByClass(note.Note)[0]
>>> voiceLeading.getVerticalSliceFromObject(n1, c)
<music21.voiceLeading.VerticalSlice contentDict={0: [<music21.note.Note F>], 1: [<music21.note.Note F>], 2: [<music21.note.Note C>], 3: [<music21.note.Note A>], 4: [<music21.note.Note F>]}

VoiceLeadingQuartet

Inherits from: Music21Object, JSONSerializer

class music21.voiceLeading.VoiceLeadingQuartet(v1n1=None, v1n2=None, v2n1=None, v2n2=None, key=C major)

An object consisting of four pitches: v1n1, v1n2, v2n1, v2n2 where v1n1 moves to v1n2 at the same time as v2n1 moves to v2n2.

Necessary for classifying types of voice-leading motion

VoiceLeadingQuartet attributes

fifth

An Interval class that encapsulates both Chromatic and Diatonic intervals all in one model.

The interval is specified either as named arguments, a DiatonicInterval and a ChromaticInterval, or two Note objects, from which both a ChromaticInterval and DiatonicInterval are derived.

>>> from music21 import *
>>> n1 = note.Note('c3')
>>> n2 = note.Note('c5')
>>> aInterval = interval.Interval(noteStart=n1, noteEnd=n2)
>>> aInterval
<music21.interval.Interval P15>
>>> aInterval.name
'P15'

Reduce to a single octave:

>>> aInterval.simpleName
'P1'

Reduce to no more than an octave:

>>> aInterval.semiSimpleName
'P8'

An interval can also be specified directly

>>> aInterval = interval.Interval('m3')
>>> aInterval
<music21.interval.Interval m3>
>>> aInterval = interval.Interval('M3')
>>> aInterval
<music21.interval.Interval M3>
>>> aInterval = interval.Interval('p5')
>>> aInterval
<music21.interval.Interval P5>
>>> aInterval.isChromaticStep
False
>>> aInterval.isDiatonicStep
False
>>> aInterval.isStep
False
>>> aInterval = interval.Interval('half')
>>> aInterval
<music21.interval.Interval m2>
>>> aInterval.isChromaticStep
True
>>> aInterval.isDiatonicStep
True
>>> aInterval.isStep
True
>>> aInterval = interval.Interval('-h')
>>> aInterval
<music21.interval.Interval m-2>
>>> aInterval.directedName
'm-2'
>>> aInterval.name
'm2'
>>> aInterval = interval.Interval(3)
>>> aInterval
<music21.interval.Interval m3>
>>> aInterval = interval.Interval(7)
>>> aInterval
<music21.interval.Interval P5>
>>> n1 = note.Note('c3')
>>> n2 = note.Note('g3')
>>> aInterval = interval.Interval(noteStart=n1, noteEnd=n2)
>>> aInterval
<music21.interval.Interval P5>
>>> aInterval = interval.Interval(noteStart=n1, noteEnd=None)
Traceback (most recent call last):
IntervalException: either both the starting and the ending note.Note must be given or neither can be given.  You cannot have one without the other.
>>> aInterval = interval.DiatonicInterval('major', 'third')
>>> bInterval = interval.ChromaticInterval(4)
>>> cInterval = interval.Interval(diatonic=aInterval, chromatic=bInterval)
>>> cInterval
<music21.interval.Interval M3>
>>> cInterval = interval.Interval(diatonic=aInterval, chromatic=None)
Traceback (most recent call last):
IntervalException: either both a DiatonicInterval and a ChromaticInterval object have to be given or neither can be given.  You cannot have one without the other.

Two Intervals are the same if their Chromatic and Diatonic intervals are the same. N.B. that interval.Interval(‘a4’) != ‘a4’ – maybe it should...

octave

An Interval class that encapsulates both Chromatic and Diatonic intervals all in one model.

The interval is specified either as named arguments, a DiatonicInterval and a ChromaticInterval, or two Note objects, from which both a ChromaticInterval and DiatonicInterval are derived.

>>> from music21 import *
>>> n1 = note.Note('c3')
>>> n2 = note.Note('c5')
>>> aInterval = interval.Interval(noteStart=n1, noteEnd=n2)
>>> aInterval
<music21.interval.Interval P15>
>>> aInterval.name
'P15'

Reduce to a single octave:

>>> aInterval.simpleName
'P1'

Reduce to no more than an octave:

>>> aInterval.semiSimpleName
'P8'

An interval can also be specified directly

>>> aInterval = interval.Interval('m3')
>>> aInterval
<music21.interval.Interval m3>
>>> aInterval = interval.Interval('M3')
>>> aInterval
<music21.interval.Interval M3>
>>> aInterval = interval.Interval('p5')
>>> aInterval
<music21.interval.Interval P5>
>>> aInterval.isChromaticStep
False
>>> aInterval.isDiatonicStep
False
>>> aInterval.isStep
False
>>> aInterval = interval.Interval('half')
>>> aInterval
<music21.interval.Interval m2>
>>> aInterval.isChromaticStep
True
>>> aInterval.isDiatonicStep
True
>>> aInterval.isStep
True
>>> aInterval = interval.Interval('-h')
>>> aInterval
<music21.interval.Interval m-2>
>>> aInterval.directedName
'm-2'
>>> aInterval.name
'm2'
>>> aInterval = interval.Interval(3)
>>> aInterval
<music21.interval.Interval m3>
>>> aInterval = interval.Interval(7)
>>> aInterval
<music21.interval.Interval P5>
>>> n1 = note.Note('c3')
>>> n2 = note.Note('g3')
>>> aInterval = interval.Interval(noteStart=n1, noteEnd=n2)
>>> aInterval
<music21.interval.Interval P5>
>>> aInterval = interval.Interval(noteStart=n1, noteEnd=None)
Traceback (most recent call last):
IntervalException: either both the starting and the ending note.Note must be given or neither can be given.  You cannot have one without the other.
>>> aInterval = interval.DiatonicInterval('major', 'third')
>>> bInterval = interval.ChromaticInterval(4)
>>> cInterval = interval.Interval(diatonic=aInterval, chromatic=bInterval)
>>> cInterval
<music21.interval.Interval M3>
>>> cInterval = interval.Interval(diatonic=aInterval, chromatic=None)
Traceback (most recent call last):
IntervalException: either both a DiatonicInterval and a ChromaticInterval object have to be given or neither can be given.  You cannot have one without the other.

Two Intervals are the same if their Chromatic and Diatonic intervals are the same. N.B. that interval.Interval(‘a4’) != ‘a4’ – maybe it should...

unison

An Interval class that encapsulates both Chromatic and Diatonic intervals all in one model.

The interval is specified either as named arguments, a DiatonicInterval and a ChromaticInterval, or two Note objects, from which both a ChromaticInterval and DiatonicInterval are derived.

>>> from music21 import *
>>> n1 = note.Note('c3')
>>> n2 = note.Note('c5')
>>> aInterval = interval.Interval(noteStart=n1, noteEnd=n2)
>>> aInterval
<music21.interval.Interval P15>
>>> aInterval.name
'P15'

Reduce to a single octave:

>>> aInterval.simpleName
'P1'

Reduce to no more than an octave:

>>> aInterval.semiSimpleName
'P8'

An interval can also be specified directly

>>> aInterval = interval.Interval('m3')
>>> aInterval
<music21.interval.Interval m3>
>>> aInterval = interval.Interval('M3')
>>> aInterval
<music21.interval.Interval M3>
>>> aInterval = interval.Interval('p5')
>>> aInterval
<music21.interval.Interval P5>
>>> aInterval.isChromaticStep
False
>>> aInterval.isDiatonicStep
False
>>> aInterval.isStep
False
>>> aInterval = interval.Interval('half')
>>> aInterval
<music21.interval.Interval m2>
>>> aInterval.isChromaticStep
True
>>> aInterval.isDiatonicStep
True
>>> aInterval.isStep
True
>>> aInterval = interval.Interval('-h')
>>> aInterval
<music21.interval.Interval m-2>
>>> aInterval.directedName
'm-2'
>>> aInterval.name
'm2'
>>> aInterval = interval.Interval(3)
>>> aInterval
<music21.interval.Interval m3>
>>> aInterval = interval.Interval(7)
>>> aInterval
<music21.interval.Interval P5>
>>> n1 = note.Note('c3')
>>> n2 = note.Note('g3')
>>> aInterval = interval.Interval(noteStart=n1, noteEnd=n2)
>>> aInterval
<music21.interval.Interval P5>
>>> aInterval = interval.Interval(noteStart=n1, noteEnd=None)
Traceback (most recent call last):
IntervalException: either both the starting and the ending note.Note must be given or neither can be given.  You cannot have one without the other.
>>> aInterval = interval.DiatonicInterval('major', 'third')
>>> bInterval = interval.ChromaticInterval(4)
>>> cInterval = interval.Interval(diatonic=aInterval, chromatic=bInterval)
>>> cInterval
<music21.interval.Interval M3>
>>> cInterval = interval.Interval(diatonic=aInterval, chromatic=None)
Traceback (most recent call last):
IntervalException: either both a DiatonicInterval and a ChromaticInterval object have to be given or neither can be given.  You cannot have one without the other.

Two Intervals are the same if their Chromatic and Diatonic intervals are the same. N.B. that interval.Interval(‘a4’) != ‘a4’ – maybe it should...

Attributes without Documentation: hIntervals, vIntervals

Attributes inherited from Music21Object: classSortOrder, hideObjectOnPrint, id, isSpanner, isStream

VoiceLeadingQuartet properties

key

No documentation.

v1n1
>>> from music21 import *
>>> vl = VoiceLeadingQuartet('C', 'D', 'E', 'F')
>>> vl.v1n1
<music21.note.Note C>
v1n2
>>> from music21 import *
>>> vl = VoiceLeadingQuartet('C', 'D', 'E', 'F')
>>> vl.v1n2
<music21.note.Note D>
v2n1
>>> from music21 import *
>>> vl = VoiceLeadingQuartet('C', 'D', 'E', 'F')
>>> vl.v2n1
<music21.note.Note E>
v2n2
>>> from music21 import *
>>> vl = VoiceLeadingQuartet('C', 'D', 'E', 'F')
>>> vl.v2n2
<music21.note.Note F>

Properties inherited from Music21Object: activeSite, beat, beatDuration, beatStr, beatStrength, classes, derivationHierarchy, duration, measureNumber, offset, priority, seconds

Properties inherited from JSONSerializer: json

VoiceLeadingQuartet methods

antiParallelMotion(simpleName=None)

Returns true if the simple interval before is the same as the simple interval after and the motion is contrary. if simpleName is specified as an Interval object or a string then it only returns true if the simpleName of both intervals is the same as simpleName (i.e., use to find antiParallel fifths)

>>> from music21 import *
>>> n11 = note.Note("C4")
>>> n12 = note.Note("D3") # descending 7th
>>> n21 = note.Note("G4")
>>> n22 = note.Note("A4") # ascending 2nd
>>> vlq1 = voiceLeading.VoiceLeadingQuartet(n11, n12, n21, n22)
>>> vlq1.antiParallelMotion()
True
>>> vlq1.antiParallelMotion('M2')
False
>>> vlq1.antiParallelMotion('P5')
True

We can also use interval objects >>> p5Obj = interval.Interval(“P5”) >>> p8Obj = interval.Interval(‘P8’) >>> vlq1.antiParallelMotion(p5Obj) True >>> p8Obj = interval.Interval(‘P8’) >>> vlq1.antiParallelMotion(p8Obj) False

>>> n1 = note.Note('G4')
>>> n2 = note.Note('G4')
>>> m1 = note.Note('G4')
>>> m2 = note.Note('G3')
>>> vl2 = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl2.antiParallelMotion()
False
closesIncorrectly()

returns true if closing harmonic interval is a P8 or PU and the interval approaching the close is 6 - 8, 10 - 8, or 3 - U. Must be in contrary motion, and if in minor key, the leading tone resolves to the tonic.

>>> from music21 import *
>>> vl = VoiceLeadingQuartet('C#', 'D', 'E', 'D')
>>> vl.key = key.Key('d')
>>> vl.closesIncorrectly()
False

>>> vl = VoiceLeadingQuartet('B3', 'C4', 'G3', 'C2')
>>> vl.key = key.Key('C')
>>> vl.closesIncorrectly()
False
>>> vl = VoiceLeadingQuartet('F', 'G', 'D', 'G')
>>> vl.key = key.Key('g')
>>> vl.closesIncorrectly()
True

>>> vl = VoiceLeadingQuartet('C#4', 'D4', 'A2', 'D3', key='D')
>>> vl.closesIncorrectly()
True
contraryMotion()

returns True if both voices move in opposite directions

>>> from music21 import *
>>> n1 = note.Note('G4')
>>> n2 = note.Note('G4')
>>> m1 = note.Note('G4')
>>> m2 = note.Note('G4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.contraryMotion() #no motion, so oblique motion will give False
False
>>> n2.octave = 5
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.contraryMotion()
False
>>> m2.octave = 5
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.contraryMotion()
False
>>> m2 = note.Note('A5')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.contraryMotion()
False
>>> m2 = note.Note('C4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.contraryMotion()
True
hiddenFifth()

No documentation.

hiddenInterval(thisInterval)

n.b. – this method finds ALL hidden intervals, not just those that are forbidden under traditional common practice counterpoint rules. Takes thisInterval, an Interval object.

>>> from music21 import *
>>> n1 = note.Note('C4')
>>> n2 = note.Note('G4')
>>> m1 = note.Note('B4')
>>> m2 = note.Note('D5')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.hiddenInterval(Interval('P5'))
True
>>> n1 = note.Note('E4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.hiddenInterval(Interval('P5'))
False
>>> m2.octave = 6
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.hiddenInterval(Interval('P5'))
False
hiddenOctave()

No documentation.

improperResolution()

checks whether the voice-leading quartet resolves correctly according to standard counterpoint rules. If the first harmony is dissonant (d5, A4, or m7) it checks that these are correctly resolved. If the first harmony is consonant, True is returned.

The key parameter should be specified to check for motion in the bass from specific note degrees. Default key is C Major.

Diminished Fifth: in by contrary motion to a third, with 7 resolving up to 1 in the bass Augmented Fourth: out by contrary motion to a sixth, with chordal seventh resolving down to a third in the bass. Minor Seventh: In to a third with a leap form 5 to 1 in the bass

>>> from music21 import *
>>> n1 = note.Note('B-4')
>>> n2 = note.Note('A4')
>>> m1 = note.Note('E4')
>>> m2 = note.Note('F4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.improperResolution() #d5
True

>>> n1 = note.Note('E5')
>>> n2 = note.Note('F5')
>>> m1 = note.Note('B-4')
>>> m2 = note.Note('A4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.improperResolution() #A4
True
>>> n1 = note.Note('B-4')
>>> n2 = note.Note('A4')
>>> m1 = note.Note('C4')
>>> m2 = note.Note('F4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.improperResolution() #m7
True

>>> n1 = note.Note('C4')
>>> n2 = note.Note('D4')
>>> m1 = note.Note('F4')
>>> m2 = note.Note('G4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.improperResolution() #not dissonant, true returned
False
>>> vl = VoiceLeadingQuartet('B-4', 'A4', 'C2', 'F2')
>>> vl.key = key.Key('F')
>>> vl.improperResolution() #not dissonant, true returned
False
inwardContraryMotion()

Returns true if both voices move inward by contrary motion

>>> from music21 import *
>>> n1 = note.Note('C5')
>>> n2 = note.Note('B4')
>>> m1 = note.Note('G4')
>>> m2 = note.Note('A4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.inwardContraryMotion()
True
>>> vl.outwardContraryMotion()
False
leapNotSetWithStep()

returns true if there is a leap or skip in once voice then the other voice must be a step or unison. if neither part skips then False is returned. Returns False if the two voices skip thirds in contrary motion.

>>> from music21 import *
>>> n1 = note.Note('G4')
>>> n2 = note.Note('C5')
>>> m1 = note.Note('B3')
>>> m2 = note.Note('A3')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.leapNotSetWithStep()
False

>>> n1 = note.Note('G4')
>>> n2 = note.Note('C5')
>>> m1 = note.Note('B3')
>>> m2 = note.Note('F3')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.leapNotSetWithStep()
True
>>> vl = VoiceLeadingQuartet('E', 'G', 'G', 'E')
>>> vl.leapNotSetWithStep()
False
motionType()
>>> from music21 import *
>>> n1 = note.Note('D4')
>>> n2 = note.Note('E4')
>>> m1 = note.Note('F4')
>>> m2 = note.Note('B4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.motionType()
'Similar'

>>> n1 = note.Note('A4')
>>> n2 = note.Note('C5')
>>> m1 = note.Note('D4')
>>> m2 = note.Note('F4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.motionType()
'Parallel'
noMotion()

Returns true if no voice moves at this “voice-leading” moment

>>> from music21 import *
>>> n1 = note.Note('G4')
>>> n2 = note.Note('G4')
>>> m1 = note.Note('D4')
>>> m2 = note.Note('D4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.noMotion()
True
>>> n2.octave = 5
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.noMotion()
False
obliqueMotion()

Returns true if one voice remains the same and another moves. I.e., noMotion must be False if obliqueMotion is True.

>>> from music21 import *
>>> n1 = note.Note('G4')
>>> n2 = note.Note('G4')
>>> m1 = note.Note('D4')
>>> m2 = note.Note('D4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.obliqueMotion()
False
>>> n2.octave = 5
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.obliqueMotion()
True
>>> m2.octave = 5
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.obliqueMotion()
False
opensIncorrectly()

Returns true if the opening or second harmonic interval is PU, P8, or P5, to accommodate an anacrusis. also checks to see if opening establishes tonic or dominant harmony (uses identifyAsTonicOrDominant()

>>> from music21 import *
>>> vl = VoiceLeadingQuartet('D','D','D','F#')
>>> vl.key = 'D'
>>> vl.opensIncorrectly()
False
>>> vl = VoiceLeadingQuartet('B','A','G#','A')
>>> vl.key = 'A'
>>> vl.opensIncorrectly()
False
>>> vl = VoiceLeadingQuartet('A', 'A', 'F#', 'D')
>>> vl.key = 'A'
>>> vl.opensIncorrectly()
False

>>> vl = VoiceLeadingQuartet('C#', 'C#', 'D', 'E')
>>> vl.key = 'A'
>>> vl.opensIncorrectly()
True
>>> vl = VoiceLeadingQuartet('B', 'B', 'A', 'A')
>>> vl.key = 'C'
>>> vl.opensIncorrectly()
True
outwardContraryMotion()

Returns true if both voices move outward by contrary motion

>>> from music21 import *
>>> n1 = note.Note('D5')
>>> n2 = note.Note('E5')
>>> m1 = note.Note('G4')
>>> m2 = note.Note('F4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.outwardContraryMotion()
True
>>> vl.inwardContraryMotion()
False
parallelFifth()

Returns true if the motion is a parallel Perfect Fifth (or antiparallel) or Octave duplication

>>> VoiceLeadingQuartet(Note("C4"), Note("D4"), Note("G4"), Note("A4")).parallelFifth()
True
>>> VoiceLeadingQuartet(Note("C4"), Note("D4"), Note("G5"), Note("A5")).parallelFifth()
True
>>> VoiceLeadingQuartet(Note("C4"), Note("D#4"), Note("G4"), Note("A4")).parallelFifth()
False
parallelInterval(thisInterval)

Returns true if there is a parallel motion or antiParallel motion of this type (thisInterval should be an Interval object)

>>> n11 = Note("C4")
>>> n12a = Note("D4") # ascending 2nd
>>> n12b = Note("D3") # descending 7th

>>> n21 = Note("G4")
>>> n22a = Note("A4") # ascending 2nd
>>> n22b = Note("B4") # ascending 3rd
>>> vlq1 = VoiceLeadingQuartet(n11, n12a, n21, n22a)
>>> vlq1.parallelInterval(Interval("P5"))
True
>>> vlq1.parallelInterval(Interval("P8"))
False

Antiparallel fifths also are true

>>> vlq2 = VoiceLeadingQuartet(n11, n12b, n21, n22a)
>>> vlq2.parallelInterval(Interval("P5"))
True

Non-parallel intervals are, of course, False >>> vlq3 = VoiceLeadingQuartet(n11, n12a, n21, n22b) >>> vlq3.parallelInterval(Interval(“P5”)) False

parallelMotion(requiredInterval=None)

returns True if both voices move with the same interval or an octave duplicate of the interval. if requiredInterval is given then returns True only if the parallel interval is that simple interval.

>>> from music21 import *
>>> n1 = note.Note('G4')
>>> n2 = note.Note('G4')
>>> m1 = note.Note('G4')
>>> m2 = note.Note('G4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.parallelMotion() #no motion, so oblique motion will give False
False
>>> n2.octave = 5
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.parallelMotion()
False
>>> m2.octave = 5
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.parallelMotion()
True
>>> vl.parallelMotion('P8')
True
>>> vl.parallelMotion('M6')
False

>>> m2 = note.Note('A5')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.parallelMotion()
False
parallelOctave()

Returns true if the motion is a parallel Perfect Octave

[ a concept so abhorrent we shudder to illustrate it with an example, but alas, we must ]

>>> VoiceLeadingQuartet(Note("C4"), Note("D4"), Note("C5"), Note("D5")).parallelOctave()
True
>>> VoiceLeadingQuartet(Note("C4"), Note("D4"), Note("C6"), Note("D6")).parallelOctave()
True
>>> VoiceLeadingQuartet(Note("C4"), Note("D4"), Note("C4"), Note("D4")).parallelOctave()
False
parallelUnison()

Returns true if the motion is a parallel Perfect Unison (and not Perfect Octave, etc.)

>>> VoiceLeadingQuartet(Note("C4"), Note("D4"), Note("C4"), Note("D4")).parallelUnison()
True
>>> VoiceLeadingQuartet(Note("C4"), Note("D4"), Note("C5"), Note("D5")).parallelUnison()
False
parallelUnisonOrOctave()
>>> VoiceLeadingQuartet(Note("C4"), Note("D4"), Note("C3"), Note("D3")).parallelUnisonOrOctave()
True
>>> VoiceLeadingQuartet(Note("C4"), Note("D4"), Note("C4"), Note("D4")).parallelUnisonOrOctave()
True
similarMotion()

Returns true if the two voices both move in the same direction. Parallel Motion will also return true, as it is a special case of similar motion. If there is no motion, returns False.

>>> from music21 import *
>>> n1 = note.Note('G4')
>>> n2 = note.Note('G4')
>>> m1 = note.Note('G4')
>>> m2 = note.Note('G4')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.similarMotion()
False
>>> n2.octave = 5
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.similarMotion()
False
>>> m2.octave = 5
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.similarMotion()
True
>>> m2 = note.Note('A5')
>>> vl = VoiceLeadingQuartet(n1, n2, m1, m2)
>>> vl.similarMotion()
True

Methods inherited from Music21Object: searchActiveSiteByAttr(), getContextAttr(), setContextAttr(), addContext(), addLocation(), addLocationAndActiveSite(), freezeIds(), getAllContextsByClass(), getCommonSiteIds(), getCommonSites(), getContextByClass(), getOffsetBySite(), getSiteIds(), getSites(), getSpannerSites(), hasContext(), hasSpannerSite(), isClassOrSubclass(), mergeAttributes(), next(), previous(), purgeLocations(), removeLocationBySite(), removeLocationBySiteId(), removeNonContainedLocations(), setOffsetBySite(), show(), splitAtDurations(), splitAtQuarterLength(), splitByQuarterLengths(), unfreezeIds(), unwrapWeakref(), wrapWeakref(), write()

Methods inherited from JSONSerializer: jsonAttributes(), jsonComponentFactory(), jsonPrint(), jsonRead(), jsonWrite()

ThreeNoteLinearSegment

Inherits from: NNoteLinearSegment, Music21Object, JSONSerializer

class music21.voiceLeading.ThreeNoteLinearSegment(noteListorn1=None, n2=None, n3=None)

An object consisting of three sequential notes

The middle tone in a ThreeNoteLinearSegment can be classified using methods enclosed in this class to identify it as types of embellishing tones. Further methods can be used on the entire stream to identify these as non-harmonic.

Accepts a sequence of strings, pitches, or notes.

>>> from music21 import *
>>> ex = voiceLeading.ThreeNoteLinearSegment('C#4','D4','E-4')
>>> ex.n1
<music21.note.Note C#>
>>> ex.n2
<music21.note.Note D>
>>> ex.n3
<music21.note.Note E->

>>> ex = voiceLeading.ThreeNoteLinearSegment(note.Note('A4'),note.Note('D4'),'F5')
>>> ex.n1
<music21.note.Note A>
>>> ex.n2
<music21.note.Note D>
>>> ex.n3
<music21.note.Note F>
>>> ex.iLeftToRight
<music21.interval.Interval m6>
>>> ex.iLeft
<music21.interval.Interval P-5>
>>> ex.iRight
<music21.interval.Interval m10>

if no octave specified, default octave of 4 is assumed

>>> ex2 = voiceLeading.ThreeNoteLinearSegment('a','b','c')
>>> ex2.n1
<music21.note.Note A>
>>> ex2.n1.pitch.defaultOctave
4

ThreeNoteLinearSegment attributes

Attributes inherited from Music21Object: classSortOrder, hideObjectOnPrint, id, isSpanner, isStream

ThreeNoteLinearSegment properties

iLeft

No documentation.

iLeftToRight

No documentation.

iRight

No documentation.

n1

No documentation.

n2

No documentation.

n3

No documentation.

Properties inherited from NNoteLinearSegment: melodicIntervals, noteList

Properties inherited from Music21Object: activeSite, beat, beatDuration, beatStr, beatStrength, classes, derivationHierarchy, duration, measureNumber, offset, priority, seconds

Properties inherited from JSONSerializer: json

ThreeNoteLinearSegment methods

color(color='red', noteList=[2])

color all the notes in noteList (1,2,3). Default is to color only the second note red

couldBeChromaticNeighborTone()

returns true if and only if noteToAnalyze could be a chromatic neighbor tone

>>> from music21 import *
>>> ThreeNoteLinearSegment('C3','D3','C3').couldBeChromaticNeighborTone()
False
>>> ThreeNoteLinearSegment('C3','D-3','C3').couldBeChromaticNeighborTone()
True
>>> ThreeNoteLinearSegment('C#3','D3','C#3').couldBeChromaticNeighborTone()
True
>>> ThreeNoteLinearSegment('C#3','D3','D-3').couldBeChromaticNeighborTone()
False
couldBeChromaticPassingTone()

A note could a chromatic passing tone (and therefore a passing tone in general) if the generic interval between the previous and the current is -2, 1, or 2; the generic interval between the current and next is -2, 1, 2; the two generic intervals multiply to -2 or 2 (if 4 then it’s a diatonic interval; if 1 then not a passing tone; i.e, C -> C# -> C## is not a chromatic passing tone); AND between each of the notes there is a chromatic interval of 1 or -1 and multiplied together it is 1. (i.e.: C -> D– -> D- is not a chromatic passing tone).

>>> from music21 import *
>>> voiceLeading.ThreeNoteLinearSegment('B3','C4','C#4').couldBeChromaticPassingTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('B3','C4','C#4').couldBeChromaticPassingTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('B3','B#3','C#4').couldBeChromaticPassingTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('B3','D-4','C#4').couldBeChromaticPassingTone()
False
>>> voiceLeading.ThreeNoteLinearSegment('B3','C##4','C#4').couldBeChromaticPassingTone()
False
>>> voiceLeading.ThreeNoteLinearSegment('C#4','C4','C##4').couldBeChromaticPassingTone()
False
>>> voiceLeading.ThreeNoteLinearSegment('D--4','C4','D-4').couldBeChromaticPassingTone()
False
couldBeDiatonicNeighborTone()

returns true if and only if noteToAnalyze could be a diatonic neighbor tone

>>> from music21 import *
>>> ThreeNoteLinearSegment('C3','D3','C3').couldBeDiatonicNeighborTone()
True
>>> ThreeNoteLinearSegment('C3','C#3','C3').couldBeDiatonicNeighborTone()
False
>>> ThreeNoteLinearSegment('C3','D-3','C3').couldBeDiatonicNeighborTone()
False
couldBeDiatonicPassingTone()

A note could be a diatonic passing tone (and therefore a passing tone in general) if the generic interval between the previous and the current is 2 or -2; same for the next; and both move in the same direction (that is, the two intervals multiplied by each other are 4, not -4).

>>> from music21 import *
>>> voiceLeading.ThreeNoteLinearSegment('B3','C4','C#4').couldBeDiatonicPassingTone()
False
>>> voiceLeading.ThreeNoteLinearSegment('C3','D3','E3').couldBeDiatonicPassingTone()
True
couldBeNeighborTone()

checks if noteToAnalyze could be a neighbor tone, either a diatonic neighbor tone or a chromatic neighbor tone. Does NOT check if tone is non harmonic

>>> from music21 import *
>>> voiceLeading.ThreeNoteLinearSegment('E3','F3','E3').couldBeNeighborTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('B-4','C5','B-4').couldBeNeighborTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('B4','C5','B4').couldBeNeighborTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('G4','F#4','G4').couldBeNeighborTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('E-3','F3','E-4').couldBeNeighborTone()
False
>>> voiceLeading.ThreeNoteLinearSegment('C3','D3','E3').couldBeNeighborTone()
False
>>> voiceLeading.ThreeNoteLinearSegment('A3','C3','D3').couldBeNeighborTone()
False
couldBePassingTone()

checks if the two intervals are steps and if these steps are moving in the same direction. Returns true if the tone is identified as either a chromatic passing tone or a diatonic passing tone. Only major and minor diatonic passing tones are recognized (not pentatonic or scales beyond twelve-notes). Does NOT check if tone is non harmonic

Accepts pitch or note objects; method is dependent on octave information

>>> from music21 import *
>>> voiceLeading.ThreeNoteLinearSegment('C#4','D4','E-4').couldBePassingTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('C3','D3','E3').couldBePassingTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('E-3','F3','G-3').couldBePassingTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('C3','C3','C3').couldBePassingTone()
False
>>> voiceLeading.ThreeNoteLinearSegment('A3','C3','D3').couldBePassingTone()
False

Directionality must be maintained

>>> voiceLeading.ThreeNoteLinearSegment('B##3','C4','D--4').couldBePassingTone()
False

If no octave is given then ._defaultOctave is used. This is generally octave 4

>>> voiceLeading.ThreeNoteLinearSegment('C','D','E').couldBePassingTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('C4','D','E').couldBePassingTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('C5','D','E').couldBePassingTone()
False

Method returns true if either a chromatic passing tone or a diatonic passing tone is identified. Spelling of the pitch does matter!

>>> voiceLeading.ThreeNoteLinearSegment('B3','C4','B##3').couldBePassingTone()
False
>>> voiceLeading.ThreeNoteLinearSegment('A##3','C4','E---4').couldBePassingTone()
False
>>> voiceLeading.ThreeNoteLinearSegment('B3','C4','D-4').couldBePassingTone()
True
>>> voiceLeading.ThreeNoteLinearSegment('B3','C4','C#4').couldBePassingTone()
True

Methods inherited from Music21Object: searchActiveSiteByAttr(), getContextAttr(), setContextAttr(), addContext(), addLocation(), addLocationAndActiveSite(), freezeIds(), getAllContextsByClass(), getCommonSiteIds(), getCommonSites(), getContextByClass(), getOffsetBySite(), getSiteIds(), getSites(), getSpannerSites(), hasContext(), hasSpannerSite(), isClassOrSubclass(), mergeAttributes(), next(), previous(), purgeLocations(), removeLocationBySite(), removeLocationBySiteId(), removeNonContainedLocations(), setOffsetBySite(), show(), splitAtDurations(), splitAtQuarterLength(), splitByQuarterLengths(), unfreezeIds(), unwrapWeakref(), wrapWeakref(), write()

Methods inherited from JSONSerializer: jsonAttributes(), jsonComponentFactory(), jsonPrint(), jsonRead(), jsonWrite()

VerticalSlice

Inherits from: Music21Object, JSONSerializer

class music21.voiceLeading.VerticalSlice(contentDict)
A vertical slice of music21 objects that occur simultaneously in a score. The vertical slice

is instantiated by passing in a dictionary of the form {partNumber : [ music21Objects ] } Typically vertical slices are created by getVerticalSlices()

>>> from music21 import *
>>> vs1 = VerticalSlice({0:[note.Note('A4'), harmony.ChordSymbol('Cm')], 1: [note.Note('F2')]})
>>> vs1.getObjectsByClass(note.Note)
[<music21.note.Note A>, <music21.note.Note F>]
>>> vs1.getObjectsByPart(0, note.Note)
<music21.note.Note A>

VerticalSlice attributes

Attributes inherited from Music21Object: classSortOrder, hideObjectOnPrint, id, isSpanner, isStream

VerticalSlice properties

lyric

sets each element on the vertical slice to have the passed in lyric

>>> from music21 import *
>>> h = voiceLeading.VerticalSlice({1:note.Note('C'), 2:harmony.ChordSymbol('C')})
>>> h.lyric = 'vertical slice 1'
>>> h.getStream().flat.getElementsByClass(note.Note)[0].lyric
'vertical slice 1'
objects

return a list of all the music21 objects in the vertical slice

>>> from music21 import *
>>> vs1 = VerticalSlice({0:[ harmony.ChordSymbol('C'), note.Note('A4'),], 1: [note.Note('C')]})
>>> vs1.objects
[<music21.harmony.ChordSymbol C>, <music21.note.Note A>, <music21.note.Note C>]

Properties inherited from Music21Object: activeSite, beat, beatDuration, beatStr, beatStrength, classes, derivationHierarchy, duration, measureNumber, priority, seconds

Properties inherited from JSONSerializer: json

VerticalSlice methods

getObjectsByClass(classFilterList, partNums=None)
>>> from music21 import *
>>> vs1 = VerticalSlice({0:[note.Note('A4'), harmony.ChordSymbol('C')], 1: [note.Note('C')], 2: [note.Note('B'), note.Note('F#')]})
>>> vs1.getObjectsByClass('Note')
[<music21.note.Note A>, <music21.note.Note C>, <music21.note.Note B>, <music21.note.Note F#>]
>>>
>>> vs1.getObjectsByClass('Note', [1,2])
[<music21.note.Note C>, <music21.note.Note B>, <music21.note.Note F#>]
getObjectsByPart(partNum, classFilterList=None)

return the list of music21 objects associated with that part number (if more than one). returns the single object if only one. Optionally specify which type of objects to return with classFilterList

>>> from music21 import *
>>> vs1 = VerticalSlice({0:[note.Note('A4'), harmony.ChordSymbol('C')], 1: [note.Note('C')]})
>>> vs1.getObjectsByPart(0, classFilterList=['Harmony'])
<music21.harmony.ChordSymbol C>
getStream(streamVSCameFrom=None)

returns the stream representation of this vertical slice. Optionally pass in the full stream that this VS was extracted from, and correct key, meter, and time signatures will be included

>>> from music21 import *
>>> vs1 = VerticalSlice({0:[ harmony.ChordSymbol('C'), note.Note('A4'),], 1: [note.Note('C')]})
>>> len(vs1.getStream().flat.getElementsByClass(note.Note))
2
>>> len(vs1.getStream().flat.getElementsByClass('Harmony'))
1
offset(leftAlign=True)

returns the overall offset of the vertical slice. Typically, this would just be the offset of each object in the vertical slice, and each object would have the same offset. However, if the duration of one object in the slice is different than the duration of another, and that other starts after the first, but the first is still sounding, then the offsets would be different. In this case, specify leftAlign=True to return the lowest valued-offset of all the objects in the vertical slice. If you prefer the offset of the right-most starting object, then specify leftAlign=False

>>> from music21 import *
>>> s = stream.Score()
>>> n1 = note.Note('A4', quarterLength=1.0)
>>> s.append(n1)
>>> n1.offset
0.0
>>> n2 = note.Note('F2', quarterLength =0.5)
>>> s.append(n2)
>>> n2.offset
1.0
>>> vs = VerticalSlice({0:n1, 1: n2})
>>> vs.getObjectsByClass(note.Note)
[<music21.note.Note A>, <music21.note.Note F>]

>>> vs.offset(leftAlign=True)
0.0
>>> vs.offset(leftAlign=False)
1.0

Methods inherited from Music21Object: searchActiveSiteByAttr(), getContextAttr(), setContextAttr(), addContext(), addLocation(), addLocationAndActiveSite(), freezeIds(), getAllContextsByClass(), getCommonSiteIds(), getCommonSites(), getContextByClass(), getOffsetBySite(), getSiteIds(), getSites(), getSpannerSites(), hasContext(), hasSpannerSite(), isClassOrSubclass(), mergeAttributes(), next(), previous(), purgeLocations(), removeLocationBySite(), removeLocationBySiteId(), removeNonContainedLocations(), setOffsetBySite(), show(), splitAtDurations(), splitAtQuarterLength(), splitByQuarterLengths(), unfreezeIds(), unwrapWeakref(), wrapWeakref(), write()

Methods inherited from JSONSerializer: jsonAttributes(), jsonComponentFactory(), jsonPrint(), jsonRead(), jsonWrite()

VerticalSliceNTuplet

Inherits from: Music21Object, JSONSerializer

class music21.voiceLeading.VerticalSliceNTuplet(listofVerticalSlices)

a collection of n number of vertical slices

NChordLinearSegment

Inherits from: NObjectLinearSegment, Music21Object, JSONSerializer

class music21.voiceLeading.NChordLinearSegment(chordList)

NChordLinearSegment attributes

Attributes inherited from Music21Object: classSortOrder, hideObjectOnPrint, id, isSpanner, isStream

NChordLinearSegment properties

chordList
>>> from music21 import *
>>> n = NChordLinearSegment([harmony.ChordSymbol('Am'), harmony.ChordSymbol('F7'), harmony.ChordSymbol('G9')])
>>> n.chordList
[<music21.harmony.ChordSymbol Am>, <music21.harmony.ChordSymbol F7>, <music21.harmony.ChordSymbol G9>]

Properties inherited from Music21Object: activeSite, beat, beatDuration, beatStr, beatStrength, classes, derivationHierarchy, duration, measureNumber, offset, priority, seconds

Properties inherited from JSONSerializer: json

NChordLinearSegment methods

NNoteLinearSegment

Inherits from: Music21Object, JSONSerializer

class music21.voiceLeading.NNoteLinearSegment(noteList)

a list of n notes strung together in a sequence noteList = [note1, note2, note3, ..., note-n ] Once this object is created with a noteList, the noteList may not be changed

>>> from music21 import *
>>> n = NNoteLinearSegment(['A', 'C', 'D'])
>>> n.noteList
[<music21.note.Note A>, <music21.note.Note C>, <music21.note.Note D>]

NNoteLinearSegment attributes

Attributes inherited from Music21Object: classSortOrder, hideObjectOnPrint, id, isSpanner, isStream

NNoteLinearSegment properties

melodicIntervals

calculates the melodic intervals and returns them as a list, with the interval at 0 being the interval between the first and second note.

>>> from music21 import *
>>> n = NNoteLinearSegment([note.Note('A'), note.Note('B'), note.Note('C'), note.Note('D')])
>>> n.melodicIntervals
[<music21.interval.Interval M2>, <music21.interval.Interval M-7>, <music21.interval.Interval M2>]
noteList
>>> from music21 import *
>>> n = NNoteLinearSegment(['A', 'B5', 'C', 'F#'])
>>> n.noteList
[<music21.note.Note A>, <music21.note.Note B>, <music21.note.Note C>, <music21.note.Note F#>]

Properties inherited from Music21Object: activeSite, beat, beatDuration, beatStr, beatStrength, classes, derivationHierarchy, duration, measureNumber, offset, priority, seconds

Properties inherited from JSONSerializer: json

NNoteLinearSegment methods

NObjectLinearSegment

Inherits from: Music21Object, JSONSerializer

class music21.voiceLeading.NObjectLinearSegment(objectList)

TwoChordLinearSegment

Inherits from: NChordLinearSegment, NObjectLinearSegment, Music21Object, JSONSerializer

class music21.voiceLeading.TwoChordLinearSegment(chordList, chord2=None)

TwoChordLinearSegment attributes

Attributes inherited from Music21Object: classSortOrder, hideObjectOnPrint, id, isSpanner, isStream

TwoChordLinearSegment properties

TwoChordLinearSegment methods

bassInterval(type='chromatic')
>>> from music21 import *
>>> h = voiceLeading.TwoChordLinearSegment(harmony.ChordSymbol('C/E'), harmony.ChordSymbol('G'))
>>> h.bassInterval()
<music21.interval.ChromaticInterval 3>
rootInterval(type='chromatic')
>>> from music21 import *
>>> h = voiceLeading.TwoChordLinearSegment([harmony.ChordSymbol('C'), harmony.ChordSymbol('G')])
>>> h.rootInterval()
<music21.interval.ChromaticInterval 7>

Methods inherited from Music21Object: searchActiveSiteByAttr(), getContextAttr(), setContextAttr(), addContext(), addLocation(), addLocationAndActiveSite(), freezeIds(), getAllContextsByClass(), getCommonSiteIds(), getCommonSites(), getContextByClass(), getOffsetBySite(), getSiteIds(), getSites(), getSpannerSites(), hasContext(), hasSpannerSite(), isClassOrSubclass(), mergeAttributes(), next(), previous(), purgeLocations(), removeLocationBySite(), removeLocationBySiteId(), removeNonContainedLocations(), setOffsetBySite(), show(), splitAtDurations(), splitAtQuarterLength(), splitByQuarterLengths(), unfreezeIds(), unwrapWeakref(), wrapWeakref(), write()

Methods inherited from JSONSerializer: jsonAttributes(), jsonComponentFactory(), jsonPrint(), jsonRead(), jsonWrite()

VerticalSliceTriplet

Inherits from: VerticalSliceNTuplet, Music21Object, JSONSerializer

class music21.voiceLeading.VerticalSliceTriplet(listofVerticalSlices)

a collection of three vertical slices

VerticalSliceTriplet attributes

Attributes inherited from Music21Object: classSortOrder, hideObjectOnPrint, id, isSpanner, isStream

VerticalSliceTriplet properties

VerticalSliceTriplet methods

hasNeighborTone(partNumToIdentify, unaccentedOnly=False)

partNum is the part (starting with 0) to identify the passing tone for use on 3 vertical slices (3tuplet)

>>> from music21 import *
>>> vs1 = VerticalSlice({0:note.Note('E-4'), 1: note.Note('C3')})
>>> vs2 = VerticalSlice({0:note.Note('E-4'), 1: note.Note('B2')})
>>> vs3 = VerticalSlice({0:note.Note('C5'), 1: note.Note('C3')})
>>> tbtm = VerticalSliceTriplet([vs1, vs2, vs3])
>>> tbtm.hasNeighborTone(1)
True
hasPassingTone(partNumToIdentify, unaccentedOnly=False)

partNum is the part (starting with 0) to identify the passing tone for use on 3 vertical slices (3Tuplet)

>>> from music21 import *
>>> vs1 = VerticalSlice({0:note.Note('A4'), 1: note.Note('F2')})
>>> vs2 = VerticalSlice({0:note.Note('B-4'), 1: note.Note('F2')})
>>> vs3 = VerticalSlice({0:note.Note('C5'), 1: note.Note('E2')})
>>> tbtm = VerticalSliceTriplet([vs1, vs2, vs3])
>>> tbtm.hasPassingTone(0)
True

Methods inherited from Music21Object: searchActiveSiteByAttr(), getContextAttr(), setContextAttr(), addContext(), addLocation(), addLocationAndActiveSite(), freezeIds(), getAllContextsByClass(), getCommonSiteIds(), getCommonSites(), getContextByClass(), getOffsetBySite(), getSiteIds(), getSites(), getSpannerSites(), hasContext(), hasSpannerSite(), isClassOrSubclass(), mergeAttributes(), next(), previous(), purgeLocations(), removeLocationBySite(), removeLocationBySiteId(), removeNonContainedLocations(), setOffsetBySite(), show(), splitAtDurations(), splitAtQuarterLength(), splitByQuarterLengths(), unfreezeIds(), unwrapWeakref(), wrapWeakref(), write()

Methods inherited from JSONSerializer: jsonAttributes(), jsonComponentFactory(), jsonPrint(), jsonRead(), jsonWrite()