# -*- coding: utf-8 -*- # ------------------------------------------------------------------------------ # Name: harmony.py # Purpose: music21 classes for representing harmonies and chord symbols # # Authors: Michael Scott Asato Cuthbert # Beth Hadley # Jacob Tyler Walls # Christopher Ariza # # Copyright: Copyright © 2011-2024 Michael Scott Asato Cuthbert # License: BSD, see license.txt # ------------------------------------------------------------------------------ ''' An object representation of harmony, a subclass of chord, as encountered as chord symbols or roman numerals, or other chord representations with a defined root. ''' from __future__ import annotations import collections import copy import re import unittest import typing as t from music21 import base from music21 import chord from music21 import common from music21 import duration from music21 import environment from music21 import exceptions21 from music21 import interval from music21 import key from music21 import pitch from music21 import prebase from music21 import style environLocal = environment.Environment('harmony') T = t.TypeVar('T', bound='ChordSymbol') NCT = t.TypeVar('NCT', bound='NoChord') if t.TYPE_CHECKING: from music21.figuredBass import realizerScale # -------------------------------------------------------------------------- # Y indicates this chord_type is an official XML chord type # N indicates XML does not support this chord type # Y : 'some string' indicates XML supports the chord type, but # uses a name different from what I use in this dictionary # I mostly used XML's nomenclature, but for a few of the sevenths # I just couldn't stand to adopt their names because they aren't consistent # sorry, you can't use '-' for minor, cause that's a flat in music21 # noinspection SpellCheckingInspection CHORD_TYPES = collections.OrderedDict([ ('major', ['1,3,5', ['', 'M', 'maj']]), # Y ('minor', ['1,-3,5', ['m', 'min']]), # Y ('augmented', ['1,3,#5', ['+', 'aug']]), # Y ('diminished', ['1,-3,-5', ['dim', 'o']]), # Y # sevenths ('dominant-seventh', ['1,3,5,-7', ['7', 'dom7', ]]), # Y: 'dominant' ('major-seventh', ['1,3,5,7', ['maj7', 'M7']]), # Y ('minor-major-seventh', ['1,-3,5,7', ['mM7', 'm#7', 'minmaj7']]), # Y: 'major-minor' ('minor-seventh', ['1,-3,5,-7', ['m7', 'min7']]), # Y ('augmented-major-seventh', ['1,3,#5,7', ['+M7', 'augmaj7']]), # N ('augmented-seventh', ['1,3,#5,-7', ['7+', '+7', 'aug7']]), # Y ('half-diminished-seventh', ['1,-3,-5,-7', ['ø7', 'm7b5']]), # Y: 'half-diminished' ('diminished-seventh', ['1,-3,-5,--7', ['o7', 'dim7']]), # Y ('seventh-flat-five', ['1,3,-5,-7', ['dom7dim5']]), # N # sixths ('major-sixth', ['1,3,5,6', ['6']]), # Y ('minor-sixth', ['1,-3,5,6', ['m6', 'min6']]), # Y # ninths ('major-ninth', ['1,3,5,7,9', ['M9', 'Maj9']]), # Y ('dominant-ninth', ['1,3,5,-7,9', ['9', 'dom9']]), # Y ('minor-major-ninth', ['1,-3,5,7,9', ['mM9', 'minmaj9']]), # N ('minor-ninth', ['1,-3,5,-7,9', ['m9', 'min9']]), # N ('augmented-major-ninth', ['1,3,#5,7,9', ['+M9', 'augmaj9']]), # Y ('augmented-dominant-ninth', ['1,3,#5,-7,9', ['9#5', '+9', 'aug9']]), # N ('half-diminished-ninth', ['1,-3,-5,-7,9', ['ø9']]), # N ('half-diminished-minor-ninth', ['1,-3,-5,-7,-9', ['øb9']]), # N ('diminished-ninth', ['1,-3,-5,--7,9', ['o9', 'dim9']]), # N ('diminished-minor-ninth', ['1,-3,-5,--7,-9', ['ob9', 'dimb9']]), # N # elevenths ('dominant-11th', ['1,3,5,-7,9,11', ['11', 'dom11']]), # Y ('major-11th', ['1,3,5,7,9,11', ['M11', 'Maj11']]), # Y ('minor-major-11th', ['1,-3,5,7,9,11', ['mM11', 'minmaj11']]), # N ('minor-11th', ['1,-3,5,-7,9,11', ['m11', 'min11']]), # Y ('augmented-major-11th', ['1,3,#5,7,9,11', ['+M11', 'augmaj11']]), # N ('augmented-11th', ['1,3,#5,-7,9,11', ['+11', 'aug11']]), # N ('half-diminished-11th', ['1,-3,-5,-7,9,11', ['ø11']]), # N ('diminished-11th', ['1,-3,-5,--7,9,11', ['o11', 'dim11']]), # N # thirteenths ('major-13th', ['1,3,5,7,9,11,13', ['M13', 'Maj13']]), # Y ('dominant-13th', ['1,3,5,-7,9,11,13', ['13', 'dom13']]), # Y ('minor-major-13th', ['1,-3,5,7,9,11,13', ['mM13', 'minmaj13']]), # N ('minor-13th', ['1,-3,5,-7,9,11,13', ['m13', 'min13']]), # Y ('augmented-major-13th', ['1,3,#5,7,9,11,13', ['+M13', 'augmaj13']]), # N ('augmented-dominant-13th', ['1,3,#5,-7,9,11,13', ['+13', 'aug13']]), # N ('half-diminished-13th', ['1,-3,-5,-7,9,11,13', ['ø13']]), # N # other ('suspended-second', ['1,2,5', ['sus2']]), # Y ('suspended-fourth', ['1,4,5', ['sus', 'sus4']]), # Y ('suspended-fourth-seventh', ['1,4,5,-7', ['7sus', '7sus4']]), # Y ('Neapolitan', ['1,-2,3,-5', ['N6']]), # Y ('Italian', ['1,#4,-6', ['It+6', 'It']]), # Y ('French', ['1,2,#4,-6', ['Fr+6', 'Fr']]), # Y ('German', ['1,-3,#4,-6', ['Gr+6', 'Ger']]), # Y ('pedal', ['1', ['pedal']]), # Y ('power', ['1,5', ['power']]), # Y ('Tristan', ['1,#4,#6,#9', ['tristan']]), # Y ]) # these are different names used by MusicXML and others, # and the authoritative name that they resolve to CHORD_ALIASES = {'dominant': 'dominant-seventh', 'major-minor': 'minor-major-seventh', 'half-diminished': 'half-diminished-seventh', } # ------------------------------------------------------------------------------ class HarmonyException(exceptions21.Music21Exception): pass # ------------------------------------------------------------------------------ class Harmony(chord.Chord): ''' Harmony objects in music21 are a special type of chord - they retain all the same functionality as a chord (and inherit from chord directly), although they have special representations symbolically. They contain a figure representation, a shorthand, for the actual pitches they contain. This shorthand is commonly used on musical scores rather than writing out the chord pitches. Thus, each harmony object has an attribute, self.writeAsChord that dictates whether the object will be written to a score as a chord (with pitches realized) or with just the figure (as in Chord Symbols). Most users should start with the ChordSymbol class or the RomanNumeral class. The Harmony object is primarily a base object for defining other sorts of objects: >>> c6 = harmony.ChordSymbol('C/E') >>> c6 By default, Harmony objects just float above the score and are a sort of analytical object. To make them also count as pitches in a score, use `writeAsChord=True` >>> c6.writeAsChord = True >>> c6 Or individual components can be specified: >>> c6_again = harmony.ChordSymbol(root='C', bass='E', kind='major') >>> c6_again It is also possible to instantiate an empty Harmony object and then set components later, but this is an advanced and delicate operation: >>> h = harmony.ChordSymbol() >>> h.root('B-3') >>> h.bass('D', allow_add=True) >>> h.inversion(1, transposeOnSet=False) >>> h.addChordStepModification(harmony.ChordStepModification('add', 4)) >>> h >>> h = harmony.ChordSymbol('C7/E') >>> h.root() >>> h.bass() >>> h.inversion() 1 >>> h.isSeventh() True >>> [str(p) for p in h.pitches] ['E3', 'G3', 'B-3', 'C4'] >>> sus = harmony.ChordSymbol('Dsus4') >>> sus.root() Accepts a keyword 'updatePitches'. By default, it is `True`, but can be set to `False` to initialize faster if pitches are not needed. ''' # sort harmony just before notes and chords and other default objects classSortOrder = base.Music21Object.classSortOrder - 1 _styleClass = style.TextStyle # INITIALIZER # def __init__(self, figure: str|None = None, root: str|pitch.Pitch|None = None, bass: str|pitch.Pitch|None = None, inversion: int|None = None, updatePitches: bool = True, **keywords ): super().__init__(**keywords) self._writeAsChord = False # TODO: Deal with the roman numeral property of harmonies. # MusicXML documentation is ambiguous: # A root is a pitch name like C, D, E, where a function is an # indication like I, II, III. It is an either/or choice to avoid # data inconsistency. # a romanNumeral numeral object, musicxml stores this within a node # called which might conflict with the Harmony self._roman = None # specify an array of degree alteration objects self.chordStepModifications: list[ChordStepModification] = [] self._degreesList: list[str] = [] self._key = None # senseless to parse inversion until chord members are populated self._updateFromParameters(root=root, bass=bass) # figure is the string representation of a Harmony object # for example, for Chord Symbols the figure might be 'Cm7' # for roman numerals, the figure might be 'I7' self._figure = figure if self._figure: self._parseFigure() # if the bass is not specified, but the root is, # assume the bass and root are identical and # assign the values accordingly if 'bass' not in self._overrides and 'root' in self._overrides: self.bass(self._overrides['root'], allow_add=True) if (updatePitches and ( self._figure # == '' or is not None or 'root' in self._overrides or 'bass' in self._overrides)): self._updatePitches() self._updateFromParameters(root=root, bass=bass, inversion=inversion) # SPECIAL METHODS # def _reprInternal(self): summary = self.figure if self.writeAsChord: summary += ': ' summary += ' '.join([p.name for p in self.pitches]) return summary # PROTECTED METHODS # def _parseFigure(self): ''' subclass this in extensions (protected in TypeScript/Java speak) ''' return def _updatePitches(self): ''' subclass this in extensions (protected in TypeScript/Java speak) ''' return def _updateFromParameters( self, root: str|pitch.Pitch|None, bass: str|pitch.Pitch|None, inversion: int|None = None ) -> None: ''' This method must be called twice, once before the pitches are rendered, and once after. This is because after the pitches are rendered, the root() and bass() become reset by the chord class, but we want the objects to retain their initial root, bass, and inversion. ''' if root and isinstance(root, str): root = common.cleanedFlatNotation(root) self.root(pitch.Pitch(root, octave=3)) elif root is not None: self.root(root) # set inversion first... if inversion is not None: self.inversion(inversion, transposeOnSet=True) # and then bass. if bass and isinstance(bass, str): bass = common.cleanedFlatNotation(bass) self.bass(pitch.Pitch(bass, octave=3), allow_add=True) elif bass is not None: self.bass(bass, allow_add=True) # PUBLIC PROPERTIES # @property def figure(self): ''' Get or set the figure of the harmony object. The figure is the character (string) representation of the object. For example, 'I', 'CM', '3#'. When you instantiate a harmony object, if you pass in a figure it is stored internally and returned when you access the figure property. If you don't instantiate the object with a figure, this property calls :meth:`music21.harmony.Harmony.findFigure` method which deduces the figure provided other information about the object, especially the chord. If the pitches of the harmony object have been modified after being instantiated, call :meth:`music21.harmony.Harmony.findFigure` to deduce the new figure. >>> h = harmony.ChordSymbol('CM') >>> h.figure 'CM' >>> harmony.ChordSymbol(root='C', bass='A', kind='minor').figure 'Cm/A' >>> h.bass(note.Note('E')) >>> h.figure 'CM' OMIT_FROM_DOCS Fixed storing deduced figures by avoiding duplicate chordStepModifications: >>> h = harmony.ChordSymbol('CM7omit5') >>> h.addChordStepModification(harmony.ChordStepModification(modType='add', degree=4)) >>> h.findFigure() 'Cmaj7 subtract 5 add 4' >>> h.figure 'CM7omit5' >>> h.figure = h.findFigure() >>> h.figure 'Cmaj7 subtract 5 add 4' ''' if self._figure is None: return self.findFigure() else: return self._figure @figure.setter def figure(self, value): self._figure = value if self._figure: self._parseFigure() self._updatePitches() @property def key(self): ''' Gets or sets the current Key (or Scale object) associated with this Harmony object. For a given RomanNumeral object. Each sub-classed harmony object may treat this property differently, for example Roman Numeral objects update the pitches when the key is changed, but chord symbol objects do not and the key provides more information about the musical context from where the harmony object was extracted. >>> r1 = roman.RomanNumeral('V') >>> r1.pitches (, , ) >>> r1.key = key.Key('A') >>> r1.pitches (, , ) Changing the key for a ChordSymbol object does nothing to its pitches, since it's not dependent on key: >>> h1 = harmony.ChordSymbol('D-m11') >>> [str(p) for p in h1.pitches] ['D-2', 'F-2', 'A-2', 'C-3', 'E-3', 'G-3'] >>> h1.key = 'CM' # = C-Major >>> [str(p) for p in h1.pitches] ['D-2', 'F-2', 'A-2', 'C-3', 'E-3', 'G-3'] But it should change the .romanNumeral object: >>> y = harmony.ChordSymbol('F') >>> y.key is None True >>> y.romanNumeral >>> y.key = key.Key('C') >>> y.romanNumeral ''' return self._key @key.setter def key(self, keyOrScale): if isinstance(keyOrScale, str): self._key = key.Key(keyOrScale) else: self._key = keyOrScale self._roman = None @property def romanNumeral(self): # noinspection SpellCheckingInspection ''' Get or set the romanNumeral numeral function of the Harmony as a :class:`~music21.romanNumeral.RomanNumeral` object. String representations accepted by RomanNumeral are also accepted. >>> h = harmony.ChordSymbol('Dmaj7') >>> h.romanNumeral >>> h.romanNumeral = 'III7' >>> h.romanNumeral >>> h.romanNumeral.key = key.Key('B') >>> h.romanNumeral >>> h.romanNumeral = roman.RomanNumeral('IV7', 'A') >>> h.romanNumeral >>> h = harmony.ChordSymbol('B-/D') >>> h.romanNumeral OMIT_FROM_DOCS Empty ChordSymbol = empty RomanNumeral: >>> harmony.ChordSymbol().romanNumeral ''' if self._roman is None: from music21 import roman if not self.pitches: return roman.RomanNumeral() # what is manipulating this so that write as chord matters? storedWriteAsChord = self._writeAsChord self.writeAsChord = True if self.key is None: self._roman = roman.romanNumeralFromChord(self, key.Key(self.root())) else: self._roman = roman.romanNumeralFromChord(self, self.key) self._writeAsChord = storedWriteAsChord return self._roman @romanNumeral.setter def romanNumeral(self, value): if hasattr(value, 'classes') and 'RomanNumeral' in value.classes: self._roman = value return from music21 import roman try: # try to create self._roman = roman.RomanNumeral(value) return except exceptions21.Music21Exception: pass raise HarmonyException(f'not a valid pitch specification: {value}') @property def writeAsChord(self): ''' Boolean attribute of all harmony objects that specifies how this object will be written to the rendered output (such as musicxml). If `True` (default for romanNumerals), the chord with pitches is written. If False (default for ChordSymbols) the harmony symbol is written. For `NoChord` objects, writeAsChord means to write as a rest. ''' return self._writeAsChord @writeAsChord.setter def writeAsChord(self, val): self._writeAsChord = val # try: # self._updatePitches() # except exceptions21.Music21Exception: # pass if val and self.duration.quarterLength == 0: self.duration = duration.Duration(1) # PUBLIC METHODS # def addChordStepModification(self, degree, *, updatePitches=True): ''' Add a harmony degree specification to this Harmony as a :class:`~music21.harmony.ChordStepModification` object. >>> hd = harmony.ChordStepModification('add', 4) >>> h = harmony.ChordSymbol() >>> h.addChordStepModification(hd) >>> h.addChordStepModification('juicy') Traceback (most recent call last): music21.harmony.HarmonyException: cannot add this object as a degree: juicy Alteration will also impact the pitches, if the keyword argument updatePitches is given as True >>> h = harmony.ChordSymbol('C') >>> mod = harmony.ChordStepModification('alter', 5, -1) >>> h.addChordStepModification(mod, updatePitches=True) >>> h.pitches (, , ) * Changed in v7: updatePitches is True by default ''' if not isinstance(degree, ChordStepModification): # TODO: possibly create ChordStepModification objects from other # specifications raise HarmonyException( f'cannot add this object as a degree: {degree}') if degree not in self.chordStepModifications: self.chordStepModifications.append(degree) if updatePitches: self._updatePitches() def findFigure(self): return 'No Figure Representation' def getChordStepModifications(self): ''' Return all harmony degrees as a list. ''' return self.chordStepModifications # ------------------------------------------------------------------------------ class ChordStepModificationException(exceptions21.Music21Exception): pass # ------------------------------------------------------------------------------ class ChordStepModification(prebase.ProtoM21Object): ''' ChordStepModification objects define the specification of harmony degree alterations, subtractions, or additions, used in :class:`~music21.harmony.Harmony` objects, which includes harmony.ChordSymbol objects (and will include harmony.RomanNumeral objects). - degree-value element: indicates degree in chord, positive integers only - degree-alter: indicates semitone alteration of degree, positive and negative integers only - degree-type: add, alter, or subtract - if `add`: degree-alter is relative to a dominant chord (major and perfect intervals except for a minor seventh) - if `alter` or `subtract`: degree-alter is relative to degree already in the chord based on its kind element >>> hd = harmony.ChordStepModification('add', 4) >>> hd > >>> hd = harmony.ChordStepModification('alter', 3, 1) >>> hd > ''' # FROM MUSIC XML DOCUMENTATION - FOR DEVELOPER'S REFERENCE # The degree element is used to add, alter, or subtract # individual notes in the chord. The degree-value element # is a number indicating the degree of the chord (1 for # the root, 3 for third, etc). The degree-alter element # is like the alter element in notes: 1 for sharp, -1 for # flat, etc. The degree-type element can be `add`, `alter`, or # `subtract`. If the degree-type is alter or subtract, the # degree-alter is relative to the degree already in the # chord based on its kind element. If the degree-type is # `add`, the degree-alter is relative to a dominant chord # (major and perfect intervals except for a minor # seventh). The print-object attribute can be used to # keep the degree from printing separately when it has # already taken into account in the text attribute of # the kind element. The plus-minus attribute is used to # indicate if plus and minus symbols should be used # instead of sharp and flat symbols to display the degree # alteration; it is `no` by default. The degree-value and # degree-type text attributes specify how the value and # type of the degree should be displayed. # # A harmony of kind "other" can be spelled explicitly by # using a series of degree elements together with a root. # INITIALIZER # def __init__(self, modType=None, degree=None, intervalObj=None) -> None: self._modType: str|None = None # add, alter, subtract self._interval: interval.Interval # alteration of degree, alter ints in mxl self._degree: int|None = None # the degree number, where 3 is the third # use properties if defined: runs certain type conversions if modType is not None: self.modType = modType if degree is not None: self.degree = degree if intervalObj is not None: self.interval = intervalObj else: self.interval = interval.Interval('P1') # SPECIAL METHODS # def _reprInternal(self): return f'modType={self.modType} degree={self.degree} interval={self.interval}' def __eq__(self, other): return ( isinstance(other, ChordStepModification) and self.modType == other.modType and self.degree == other.degree and self.interval == other.interval ) # PUBLIC PROPERTIES # @property def degree(self): ''' Returns or sets an integer specifying the scale degree that this ChordStepModification alters. >>> hd = harmony.ChordStepModification() >>> hd.degree = 3 >>> hd.degree 3 >>> hd.degree = 'juicy' Traceback (most recent call last): music21.harmony.ChordStepModificationException: not a valid degree: juicy ''' return self._degree @degree.setter def degree(self, expr): if expr is not None and common.isNum(expr): self._degree = int(expr) # should always be an integer return raise ChordStepModificationException( f'not a valid degree: {expr}') @property def interval(self): ''' Get or set the alteration of this degree as a :class:`~music21.interval.Interval` object, generally as a type of ascending or descending augmented unison. >>> hd = harmony.ChordStepModification() >>> hd.interval = 1 >>> hd.interval >>> hd.interval = -2 >>> hd.interval >>> hd.interval = 0 >>> hd.interval >>> hd.interval = interval.Interval('m3') >>> hd.interval More than 3 half step alteration gets an interval that isn't a prime. >>> hd.interval = -4 >>> hd.interval ''' return self._interval @interval.setter def interval(self, value): if value in (None,): self._interval = None elif isinstance(value, interval.Interval): # an interval object: set directly self._interval = value else: # accept numbers to permit loading from mxl alter specs numAs = abs(value) if numAs <= 3: if numAs == 0: aStr = 'P' else: aStr = 'a' * numAs aStr += '1' if value < 0: aStr += '-' self._interval = interval.Interval(aStr) else: # try to create interval object self._interval = interval.Interval(value) @property def modType(self): ''' Get or set the ChordStepModification modification type, where permitted types are the strings add, subtract, or alter. >>> hd = harmony.ChordStepModification() >>> hd.modType = 'add' >>> hd.modType 'add' >>> hd.modType = 'juicy' Traceback (most recent call last): music21.harmony.ChordStepModificationException: not a valid degree modification type: juicy ''' return self._modType @modType.setter def modType(self, expr): if expr is not None and isinstance(expr, str): if expr.lower() in ['add', 'subtract', 'alter']: self._modType = expr.lower() return raise ChordStepModificationException( f'not a valid degree modification type: {expr}') # ------------------------------------------------------------------------------ def addNewChordSymbol(chordTypeName, fbNotationString, AbbreviationList): # noinspection SpellCheckingInspection ''' Add a new chord symbol: >>> harmony.addNewChordSymbol('BethChord', '1,3,-6,#9', ['MH', 'beth']) >>> [str(p) for p in harmony.ChordSymbol('BMH').pitches] ['B2', 'C##3', 'D#3', 'G3'] >>> harmony.ChordSymbol('Cbeth').pitches (, , , ) >>> harmony.ChordSymbol('C-beth').pitches (, , , ) OMIT_FROM_DOCS >>> harmony.ChordSymbol(root='Cb', kind='BethChord').pitches (, , , ) >>> harmony.ChordSymbol(root='C-', kind='BethChord').pitches (, , , ) >>> harmony.removeChordSymbols('BethChord') ''' CHORD_TYPES[chordTypeName] = [fbNotationString, AbbreviationList] def changeAbbreviationFor(chordType, changeTo): ''' Change the current Abbreviation used for a certain :class:`music21.harmony.ChordSymbol` chord type >>> harmony.getCurrentAbbreviationFor('minor') 'm' >>> harmony.changeAbbreviationFor('minor', 'min') >>> harmony.getCurrentAbbreviationFor('minor') 'min' OMIT_FROM_DOCS >>> harmony.changeAbbreviationFor('minor', 'm') # must change it back for the rest of doctests ''' CHORD_TYPES[chordType][1].insert(0, changeTo) def chordSymbolFigureFromChord(inChord: chord.Chord, includeChordType=False): # noinspection SpellCheckingInspection ''' Analyze the given chord, and attempt to describe its pitches using a standard chord symbol figure. The pitches of the chord are analyzed based on intervals, and compared to standard triads, sevenths, ninths, elevenths, and thirteenth chords. The type of chord therefore is determined if it matches (given certain guidelines documented below) and the figure is returned. There is no standard "chord symbol" notation, so a typical notation is used that can be easily modified if desired by changing a dictionary in the source code. Set includeChordType to true (default is False) to return a tuple, the first element being the figure and the second element the identified chord type. >>> harmony.chordSymbolFigureFromChord(chord.Chord(['C3', 'E3', 'G3'])) 'C' THIRDS >>> c = chord.Chord(['C3', 'E3', 'G3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('C', 'major') >>> c = chord.Chord(['B-3', 'D-4', 'F4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('B-m', 'minor') >>> c = chord.Chord(['F#3', 'A#3', 'C##4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('F#+', 'augmented') >>> c = chord.Chord(['C3', 'E-3', 'G-3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Cdim', 'diminished') SEVENTHS >>> c = chord.Chord(['E-3', 'G3', 'B-3', 'D-4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('E-7', 'dominant-seventh') >>> c = chord.Chord(['C3', 'E3', 'G3', 'B3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Cmaj7', 'major-seventh') >>> c = chord.Chord(['F#3', 'A3', 'C#4', 'E#4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('F#mM7', 'minor-major-seventh') >>> c = chord.Chord(['F3', 'A-3', 'C4', 'E-4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Fm7', 'minor-seventh') >>> c = chord.Chord(['F3', 'A3', 'C#4', 'E4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('F+M7', 'augmented-major-seventh') >>> c = chord.Chord(['C3', 'E3', 'G#3', 'B-3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('C7+', 'augmented-seventh') >>> c = chord.Chord(['G3', 'B-3', 'D-4', 'F4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Gø7', 'half-diminished-seventh') >>> c = chord.Chord(['C3', 'E-3', 'G-3', 'B--3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Co7', 'diminished-seventh') >>> c = chord.Chord(['B-3', 'D4', 'F-4', 'A-4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('B-dom7dim5', 'seventh-flat-five') NINTHS >>> c = chord.Chord(['C3', 'E3', 'G3', 'B3', 'D3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('CM9', 'major-ninth') >>> c = chord.Chord(['B-3', 'D4', 'F4', 'A-4', 'C4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('B-9', 'dominant-ninth') >>> c = chord.Chord(['E-3', 'G-3', 'B-3', 'D4', 'F3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('E-mM9', 'minor-major-ninth') >>> c = chord.Chord(['C3', 'E-3', 'G3', 'B-3', 'D3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Cm9', 'minor-ninth') >>> c = chord.Chord(['F#3', 'A#3', 'C##4', 'E#4', 'G#3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('F#+M9', 'augmented-major-ninth') >>> c = chord.Chord(['G3', 'B3', 'D#4', 'F4', 'A3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('G9#5', 'augmented-dominant-ninth') >>> c = chord.Chord(['C3', 'E-3', 'G-3', 'B-3', 'D3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Cø9', 'half-diminished-ninth') >>> c = chord.Chord(['B-3', 'D-4', 'F-4', 'A-4', 'C-4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('B-øb9', 'half-diminished-minor-ninth') >>> c = chord.Chord(['C3', 'E-3', 'G-3', 'B--3', 'D3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Co9', 'diminished-ninth') >>> c = chord.Chord(['F3', 'A-3', 'C-4', 'E--4', 'G-3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Fob9', 'diminished-minor-ninth') This harmony can either be CmaddD or Csus2addE-. music21 prefers the former. Change the ordering of harmony.CHORD_TYPES to switch the preference. From Bach BWV380 >>> c = chord.Chord(['C3', 'D4', 'G4', 'E-5']) >>> harmony.chordSymbolFigureFromChord(c, True) ('CmaddD', 'minor') ELEVENTHS >>> c = chord.Chord(['E-3', 'G3', 'B-3', 'D-4', 'F3', 'A-3'] ) >>> harmony.chordSymbolFigureFromChord(c, True) ('E-11', 'dominant-11th') >>> c = chord.Chord(['G3', 'B3', 'D4', 'F#4', 'A3', 'C4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('GM11', 'major-11th') >>> c = chord.Chord(['C3', 'E-3', 'G3', 'B3', 'D3', 'F3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('CmM11', 'minor-major-11th') >>> c = chord.Chord(['F#3', 'A3', 'C#4', 'E4', 'G#3', 'B3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('F#m11', 'minor-11th') >>> c = chord.Chord(['B-3', 'D4', 'F#4', 'A4', 'C4', 'E-4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('B-+M11', 'augmented-major-11th') >>> c = chord.Chord(['F3', 'A3', 'C#4', 'E-4', 'G3', 'B-3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('F+11', 'augmented-11th') >>> c = chord.Chord(['G3', 'B-3', 'D-4', 'F4', 'A3', 'C4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Gø11', 'half-diminished-11th') >>> c = chord.Chord(['E-3', 'G-3', 'B--3', 'D--4', 'F3', 'A-3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('E-o11', 'diminished-11th') THIRTEENTHS These are so tricky: music21 needs to be told what the root is in these cases all tests here are 'C' chords, but any root will work: >>> c = chord.Chord(['C3', 'E3', 'G3', 'B3', 'D4', 'F4', 'A4']) >>> c.root('C3') >>> harmony.chordSymbolFigureFromChord(c, True) ('CM13', 'major-13th') >>> c = chord.Chord(['C3', 'E3', 'G3', 'B-3', 'D4', 'F4', 'A4']) >>> c.root('C3') >>> harmony.chordSymbolFigureFromChord(c, True) ('C13', 'dominant-13th') >>> c = chord.Chord(['C3', 'E-3', 'G3', 'B3', 'D4', 'F4', 'A4']) >>> c.root('C3') >>> harmony.chordSymbolFigureFromChord(c, True) ('CmM13', 'minor-major-13th') >>> c = chord.Chord(['C3', 'E-3', 'G3', 'B-3', 'D4', 'F4', 'A4']) >>> c.root('C3') >>> harmony.chordSymbolFigureFromChord(c, True) ('Cm13', 'minor-13th') >>> c = chord.Chord(['C3', 'E3', 'G#3', 'B3', 'D4', 'F4', 'A4']) >>> c.root('C3') >>> harmony.chordSymbolFigureFromChord(c, True) ('C+M13', 'augmented-major-13th') >>> c = chord.Chord(['C3', 'E3', 'G#3', 'B-3', 'D4', 'F4', 'A4']) >>> c.root('C3') >>> harmony.chordSymbolFigureFromChord(c, True) ('C+13', 'augmented-dominant-13th') >>> c = chord.Chord(['C3', 'E-3', 'G-3', 'B-3', 'D4', 'F4', 'A4']) >>> c.root('C3') >>> harmony.chordSymbolFigureFromChord(c, True) ('Cø13', 'half-diminished-13th') Pop chords are typically not always "strictly" spelled and often certain degrees are omitted. Therefore, the following common chord omissions are permitted and the chord will still be identified correctly: * triads: none * seventh chords: none * ninth chords: fifth * eleventh chords: third and/or fifth * thirteenth chords: fifth, eleventh, ninth This chord could be minor 7th with a C4, but because this 5th is not present, it is not identified. >>> c = chord.Chord(['F3', 'A-3', 'E-4']) >>> harmony.chordSymbolFigureFromChord(c) 'Chord Symbol Cannot Be Identified' Removing the fifth G3 (fifth of chord) >>> c = chord.Chord(['C3', 'E3', 'B3', 'D3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('CM9', 'major-ninth') Chord with G3 and B-3 removed (3rd & 5th of chord) >>> c = chord.Chord(['E-3', 'D-4', 'F3', 'A-3'] ) Without a 3rd and 5th, root() algorithm can't locate the root, so we must tell it the root (or write an algorithm that assumes the root is the lowest note if the root can't be found) >>> c.root('E-3') >>> harmony.chordSymbolFigureFromChord(c, True) ('E-11', 'dominant-11th') Inversions are supported, and indicated with a '/' between the root, type-string, and bass >>> c = chord.Chord([ 'G#3', 'B-3', 'C4', 'E4',]) >>> harmony.chordSymbolFigureFromChord(c, True) ('C7+/G#', 'augmented-seventh') >>> c = chord.Chord(['G#2', 'B2', 'F#3', 'A3', 'C#4', 'E4']) >>> harmony.chordSymbolFigureFromChord(c, True) ('F#m11/G#', 'minor-11th') if the algorithm matches the chord, but omissions or subtractions are present, the chord symbol attempts to indicate this (although there is no standard way of doing this so the notation might be different from what you're familiar with). An example of using this algorithm for identifying chords "in the wild": >>> score = corpus.parse('bach/bwv380') >>> excerpt = score.measures(2, 3) >>> chfy = excerpt.chordify() >>> for c in chfy.flatten().getElementsByClass(chord.Chord): ... print(harmony.chordSymbolFigureFromChord(c)) B-7 E-maj7/B- B-7 Chord Symbol Cannot Be Identified B-7 E- B- Chord Symbol Cannot Be Identified B-/D B-7 CmaddD Cm/D E-+M7/D Cm/E- F7 Notice, however, that this excerpt contains many embellishment and non-harmonic tones, so an algorithm to truly identify the chord symbols must be as complex as any harmonic analysis algorithm, which this is not, so innately this method is flawed. And for the sake of completeness, unique chords supported by musicxml that this method can still successfully identify. Notice that the root must often be specified for this method to work. >>> c = chord.Chord(['C3', 'D3', 'G3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Csus2', 'suspended-second') >>> c.root() >>> c.bass() >>> c = chord.Chord(['C3', 'F3', 'G3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Csus', 'suspended-fourth') >>> c.root() >>> c.inversion() 0 >>> c = chord.Chord(['C3', 'D-3', 'E3', 'G-3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('CN6', 'Neapolitan') >>> c = chord.Chord(['C3', 'F#3', 'A-3']) >>> c.root('C3') >>> harmony.chordSymbolFigureFromChord(c, True) ('CIt+6', 'Italian') >>> c = chord.Chord(['C3', 'D3', 'F#3', 'A-3']) >>> c.root('C3') >>> harmony.chordSymbolFigureFromChord(c, True) ('CFr+6', 'French') >>> c = chord.Chord(['C3', 'E-3', 'F#3', 'A-3']) >>> c.root('C3') >>> harmony.chordSymbolFigureFromChord(c, True) ('CGr+6', 'German') >>> eflat = chord.Chord(['E-3']) >>> harmony.chordSymbolFigureFromChord(eflat, True) ('E-pedal', 'pedal') >>> c = chord.Chord(['C3', 'G3']) >>> harmony.chordSymbolFigureFromChord(c, True) ('Cpower', 'power') >>> c = chord.Chord(['F3', 'G#3', 'B3', 'D#4'] ) >>> c.root('F3') >>> harmony.chordSymbolFigureFromChord(c, True) ('Ftristan', 'Tristan') This algorithm works as follows: 1. chord is analyzed for root (using chord's root() ) if the root cannot be determined, error is raised be aware that the root() method determines the root based on which note has the most thirds above it this is not a consistent way to determine the root of 13th chords, for example 2. a chord vector is extracted from the chord using :meth:`music21.chord.Chord.semitonesFromChordStep` this vector extracts the following degrees: (2, 3, 4, 5, 6, 7, 9, 11, and 13) 3. this vector is converted to fbNotationString (in the form of chord step, and a '-' or '#' to indicate semitone distance) 4. the fbNotationString is matched against the CHORD_TYPES dictionary in this harmony module, although certain subtractions are permitted for example a 9th chord will still be identified correctly even if it is missing the 5th 5. the type with the most identical matches is used, and if no type matches, "Chord Type Cannot Be Identified" is returned 6. the output format for the chord symbol figure is the chord's root, the chord type's Abbreviation (saved in CHORD_TYPES dictionary), a '/' if the chord is in an inversion, and the chord's bass The chord symbol nomenclature is not entirely standardized. There are several ways to write each abbreviation. For example, an augmented triad might be symbolized with '+' or 'aug'. Thus, by default the returned symbol is the first (element 0) in the CHORD_TYPES list. For example (Eb minor eleventh chord, second inversion): root + chord-type-str + '/' + bass = 'E-min11/B-' Users who wish to change these defaults can simply change that entry in the CHORD_TYPES dictionary. >>> harmony.chordSymbolFigureFromChord(chord.Chord(['C2', 'E2', 'G2'])) 'C' >>> harmony.changeAbbreviationFor('major', 'maj') >>> harmony.chordSymbolFigureFromChord(chord.Chord(['C2', 'E2', 'G2'])) 'Cmaj' OMIT_FROM_DOCS >>> harmony.changeAbbreviationFor('major', '') ''' if not inChord.pitches: return '' try: inChord.root() except Exception as e: raise HarmonyException(str(e)) from e if len(inChord.pitches) == 1: if includeChordType: return (inChord.root().name + 'pedal', 'pedal') else: return inChord.root().name + 'pedal' d3 = inChord.semitonesFromChordStep(3) # 4 triad d5 = inChord.semitonesFromChordStep(5) # 7 triad d7 = inChord.semitonesFromChordStep(7) # 11 seventh d9 = inChord.semitonesFromChordStep(2) # 2 ninth d11 = inChord.semitonesFromChordStep(4) # 5 eleventh d13 = inChord.semitonesFromChordStep(6) # 9 thirteenth d2 = d9 d4 = d11 d6 = d13 def compare(inChordNums, givenChordNums, permittedOmissions=()): ''' inChord is the chord the user submits to analyze, givenChordNum is the chord type that the method is currently looking at to determine if it could be a match for inChord the corresponding semitones are compared, and if they do not match it is determined whether this is a permitted omission, etc. ''' m = len(givenChordNums) if m > len(inChordNums): return False if m >= 1 and inChordNums[0] != givenChordNums[0]: if (not (3 in permittedOmissions and givenChordNums[0] == 4) or inChordNums[0] is not None): return False if m >= 2 and inChordNums[1] != givenChordNums[1]: if (not (5 in permittedOmissions and givenChordNums[1] == 7) or inChordNums[1] is not None): return False if m >= 3 and inChordNums[2] != givenChordNums[2]: if (not (7 in permittedOmissions and givenChordNums[2] == 11) or inChordNums[2] is not None): return False if m >= 4 and inChordNums[3] != givenChordNums[3]: if (not (9 in permittedOmissions and givenChordNums[3] == 2) or inChordNums[3] is not None): return False if m >= 5 and inChordNums[4] != givenChordNums[4]: if (not (11 in permittedOmissions and givenChordNums[4] == 5) or inChordNums[4] is not None): return False if m >= 6 and inChordNums[5] != givenChordNums[5]: if (not (13 in permittedOmissions and givenChordNums[5] == 9) or inChordNums[5] is not None): return False return True kindStr = kind = '' isTriad = inChord.isTriad() isSeventh = inChord.isSeventh() def convertFBNotationStringToDegrees(innerKind, fbNotation): # convert the fb-notation string provided in CHORD_TYPES to chordDegrees notation types = { 3: 4, 5: 7, 7: 11, 9: 2, 11: 5, 13: 9, 2: 2, 4: 5, 6: 9, } inner_chordDegrees = [] if innerKind in CHORD_ALIASES: innerKind = CHORD_ALIASES[innerKind] if innerKind in CHORD_TYPES: for char in fbNotation.split(','): if char == '1': continue if '-' in char: alt = char.count('-') * -1 else: alt = char.count('#') degree = int(char.replace('-', '').replace('#', '')) inner_chordDegrees.append(types[degree] + alt) return inner_chordDegrees for chordKind in CHORD_TYPES: chordKindStr = getAbbreviationListGivenChordType(chordKind) fbNotationString = getNotationStringGivenChordType(chordKind) chordDegrees = convertFBNotationStringToDegrees(chordKind, fbNotationString) if not common.isListLike(chordKindStr): chordKindStr = [chordKindStr] if common.isListLike(chordDegrees): if len(chordDegrees) == 2 and isTriad: if compare((d3, d5), chordDegrees) and isTriad: kind = chordKind kindStr = chordKindStr[0] elif len(chordDegrees) == 3 and isSeventh: if compare((d3, d5, d7), chordDegrees): kind = chordKind kindStr = chordKindStr[0] elif len(chordDegrees) == 4 and d9 and not d11 and not d13: if compare((d3, d5, d7, d9), chordDegrees, permittedOmissions=(5,)): kind = chordKind kindStr = chordKindStr[0] elif len(chordDegrees) == 5 and d11 and not d13: if compare((d3, d5, d7, d9, d11), chordDegrees, permittedOmissions=(3, 5)): kind = chordKind kindStr = chordKindStr[0] elif len(chordDegrees) == 6 and d13: if compare((d3, d5, d7, d9, d11, d13), chordDegrees, permittedOmissions=(5, 11, 9)): kind = chordKind kindStr = chordKindStr[0] if not kind: # if, after all that, no chord has been found, try to match by degree instead numberOfMatchedDegrees = 0 for chordKind in CHORD_TYPES: chordKindStr = getAbbreviationListGivenChordType(chordKind) fbNotationString = getNotationStringGivenChordType(chordKind) chordDegrees = convertFBNotationStringToDegrees(chordKind, fbNotationString) if not common.isListLike(chordKindStr): chordKindStr = [chordKindStr] if common.isListLike(chordDegrees): s = fbNotationString.replace('-', '').replace('#', '') degrees = s.split(',') degrees = [int(x) for x in degrees] degrees.sort() data = {2: d2, 3: d3, 4: d4, 5: d5, 6: d6, 7: d7, 9: d9, 11: d11, 13: d13} toCompare = [] for x in degrees: if x != 1: toCompare.append(data[x]) if compare(toCompare, chordDegrees): if numberOfMatchedDegrees < len(chordDegrees): # a better match has been found! update! numberOfMatchedDegrees = len(chordDegrees) kind = chordKind kindStr = chordKindStr[0] if kind: # new algorithm makes sus chord be a sus2 in inversion: if inChord.inversion(): if kindStr == 'sus2': inChord.root(inChord.bass()) kindStr = 'sus' kind = 'suspended-fourth' cs = inChord.root().name + kindStr else: cs = inChord.root().name + kindStr + '/' + inChord.bass().name else: cs = inChord.root().name + kindStr perfect = {p.name for p in ChordSymbol(cs).pitches} inPitches = {p.name for p in inChord.pitches} if not perfect.issuperset(inPitches): # must be subtraction or deletion. additions = inPitches.difference(perfect) subtractions = perfect.difference(inPitches) if additions: cs += 'add' for a in additions: cs += (a + ',') if subtractions: cs += 'omit' for s in subtractions: cs += (s + ',') cs = cs[:-1] else: cs = 'Chord Symbol Cannot Be Identified' if includeChordType: return (cs, kind) else: return cs def chordSymbolFromChord(inChord: chord.Chord) -> ChordSymbol: ''' Get the :class:`~music21.harmony.chordSymbol` object from the chord, using :meth:`music21.harmony.Harmony.chordSymbolFigureFromChord` >>> c = chord.Chord(['D3', 'F3', 'A4', 'B-5']) >>> symbol = harmony.chordSymbolFromChord(c) >>> symbol >>> c.pitches == symbol.pitches True ''' cs = ChordSymbol(chordSymbolFigureFromChord(inChord)) cs.pitches = inChord.pitches return cs def getAbbreviationListGivenChordType(chordType): ''' Get the Abbreviation list (all allowed Abbreviations that map to this :class:`music21.harmony.ChordSymbol` object): >>> harmony.getAbbreviationListGivenChordType('minor-major-13th') ['mM13', 'minmaj13'] ''' return CHORD_TYPES[chordType][1] def getCurrentAbbreviationFor(chordType): ''' Return the current Abbreviation for a given :class:`music21.harmony.ChordSymbol` chordType: >>> harmony.getCurrentAbbreviationFor('dominant-seventh') '7' ''' return getAbbreviationListGivenChordType(chordType)[0] def getNotationStringGivenChordType(chordType): ''' Get the notation string (fb-notation style) associated with this :class:`music21.harmony.ChordSymbol` chordType >>> harmony.getNotationStringGivenChordType('German') '1,-3,#4,-6' ''' return CHORD_TYPES[chordType][0] def removeChordSymbols(chordType): ''' Remove the given chord type from the CHORD_TYPES dictionary, so it can no longer be identified or parsed by harmony methods. ''' del CHORD_TYPES[chordType] # -------------------------------------------------------------------------- realizerScaleCache: dict[tuple[str, str], realizerScale.FiguredBassScale] = {} # -------------------------------------------------------------------------- class ChordSymbol(Harmony): # noinspection SpellCheckingInspection ''' Class representing the Chord Symbols commonly found on lead sheets. Chord Symbol objects can be instantiated one of two main ways: 1. when music xml is parsed by the music21 converter, xml Chord Symbol tags are interpreted as Chord Symbol objects with a root and kind attribute. If bass is not specified, the bass is assumed to be the root 2. by creating a chord symbol object with music21 by passing in the expression commonly found on leadsheets. Due to the relative diversity of lead sheet chord syntax, not all expressions are supported. Consult the examples for the supported syntax, or email us for help. All :class:`~music21.harmony.ChordSymbol` inherit from :class:`~music21.chord.Chord` so you can consider these objects as chords, although they have a unique representation in a score. ChordSymbols, unlike chords, by default appear as chord symbols in a score and have duration of 0. To obtain the chord representation of the `ChordSymbol` in the score, change :attr:`~music21.harmony.Harmony.writeAsChord` to True. Unless otherwise specified, the duration of this chord object will become 1.0. If you have a leadsheet, run :func:`music21.harmony.realizeChordSymbolDurations` on the stream to assign the correct (according to offsets) duration to each harmony object.) The music xml-based approach to instantiating Chord Symbol objects: >>> cs = harmony.ChordSymbol(kind='minor', kindStr='m', root='C', bass='E-') >>> cs >>> cs.chordKind 'minor' >>> cs.root() >>> cs.bass() The second approach to creating a Chord Symbol object, by passing a regular expression (this list is not exhaustive): >>> symbols = ['', 'm', '+', 'dim', '7', ... 'M7', 'm7', 'dim7', '7+', 'm7b5', # half-diminished ... 'mM7', '6', 'm6', '9', 'Maj9', 'm9', ... '11', 'Maj11', 'm11', '13', ... 'Maj13', 'm13', 'sus2', 'sus4', ... 'N6', 'It+6', 'Fr+6', 'Gr+6', 'pedal', ... 'power', 'tristan', '/E', 'm7/E-', 'add2', ... '7omit3',] >>> for s in symbols: ... chordSymbolName = 'C' + s ... h = harmony.ChordSymbol(chordSymbolName) ... pitchNames = [str(p) for p in h.pitches] ... print('%-10s%s' % (chordSymbolName, '[' + (', '.join(pitchNames)) + ']')) C [C3, E3, G3] Cm [C3, E-3, G3] C+ [C3, E3, G#3] Cdim [C3, E-3, G-3] C7 [C3, E3, G3, B-3] CM7 [C3, E3, G3, B3] Cm7 [C3, E-3, G3, B-3] Cdim7 [C3, E-3, G-3, B--3] C7+ [C3, E3, G#3, B-3] Cm7b5 [C3, E-3, G-3, B-3] CmM7 [C3, E-3, G3, B3] C6 [C3, E3, G3, A3] Cm6 [C3, E-3, G3, A3] C9 [C3, E3, G3, B-3, D4] CMaj9 [C3, E3, G3, B3, D4] Cm9 [C3, E-3, G3, B-3, D4] C11 [C2, E2, G2, B-2, D3, F3] CMaj11 [C2, E2, G2, B2, D3, F3] Cm11 [C2, E-2, G2, B-2, D3, F3] C13 [C2, E2, G2, B-2, D3, F3, A3] CMaj13 [C2, E2, G2, B2, D3, F3, A3] Cm13 [C2, E-2, G2, B-2, D3, F3, A3] Csus2 [C3, D3, G3] Csus4 [C3, F3, G3] CN6 [C3, D-3, E3, G-3] CIt+6 [C3, F#3, A-3] CFr+6 [C3, D3, F#3, A-3] CGr+6 [C3, E-3, F#3, A-3] Cpedal [C3] Cpower [C3, G3] Ctristan [C3, D#3, F#3, A#3] C/E [E3, G3, C4] Cm7/E- [E-3, G3, B-3, C4] Cadd2 [C3, D3, E3, G3] C7omit3 [C3, G3, B-3] You can also create a Chord Symbol by writing out each degree, and any alterations to that degree: You must explicitly indicate EACH degree (a triad is NOT necessarily implied) >>> [str(p) for p in harmony.ChordSymbol('C35b7b9#11b13').pitches] ['C2', 'E2', 'G2', 'D-3', 'F#3', 'A-3', 'B-3'] >>> [str(p) for p in harmony.ChordSymbol('C35911').pitches] ['C2', 'E2', 'G2', 'D3', 'F3'] to prevent ambiguity in notation and in accordance with the rest of music21, if a root or bass is flat, the '-' must be used, and NOT 'b'. However, alterations and chord abbreviations are specified normally with the 'b' and '#' signs. >>> dFlat = harmony.ChordSymbol('D-35') >>> [str(p) for p in dFlat.pitches] ['D-3', 'F3', 'A-3'] >>> [str(p) for p in harmony.ChordSymbol('Db35').pitches] ['D3', 'F3', 'A3'] (Note that this would be much better expressed just as 'Dm'.) >>> [str(p) for p in harmony.ChordSymbol('D,35b7b9#11b13').pitches] ['D2', 'F#2', 'A2', 'E-3', 'G#3', 'B-3', 'C4'] >>> harmony.ChordSymbol('Am').pitches (, , ) >>> harmony.ChordSymbol('A-m').pitches (, , ) >>> harmony.ChordSymbol('A-m').pitches (, , ) >>> harmony.ChordSymbol('F-dim7').pitches (, , , ) Thanks to David Bolton for catching the bugs tested below: >>> [str(p) for p in harmony.ChordSymbol('C3579').pitches] ['C2', 'E2', 'G2', 'D3', 'B3'] >>> [str(p) for p in harmony.ChordSymbol('C35b79').pitches] ['C2', 'E2', 'G2', 'D3', 'B-3'] >>> [str(p) for p in harmony.ChordSymbol('C357b9').pitches] ['C2', 'E2', 'G2', 'D-3', 'B3'] When bass is not in chord: >>> cs = harmony.ChordSymbol(root='E', bass='C', kind='diminished-seventh') >>> [str(p) for p in cs.pitches] ['C2', 'E3', 'G3', 'B-3', 'D-4'] >>> cs.figure 'Eo7/C' And now, and example of parsing in the wild: >>> s = corpus.parse('leadsheet/fosterBrownHair') >>> initialSymbols = s.flatten().getElementsByClass(harmony.ChordSymbol)[0:5] >>> [[str(c.name) for c in c.pitches] for c in initialSymbols] [['F', 'A', 'C'], ['B-', 'D', 'F'], ['F', 'A', 'C'], ['C', 'E', 'G'], ['F', 'A', 'C']] Test creating an empty chordSymbol: >>> cs = harmony.ChordSymbol() >>> cs >>> cs.root('E-') >>> cs.bass('B-', allow_add=True) important: we are not asking for transposition, merely specifying the inversion that the chord should be read in (transposeOnSet = False) >>> cs.inversion(2, transposeOnSet=False) >>> cs.romanNumeral = 'I64' >>> cs.chordKind = 'major' >>> cs.chordKindStr = 'M' >>> cs ''' # INITIALIZER # def __init__(self, figure: str|None = None, root: pitch.Pitch|str|None = None, bass: pitch.Pitch|str|None = None, inversion: int|None = None, kind='', kindStr='', **keywords ): self.chordKind = kind # a string from defined list of chord symbol harmonies self.chordKindStr = kindStr # the presentation of the kind or label of symbol super().__init__(figure, root=root, bass=bass, inversion=inversion, **keywords) if 'duration' not in keywords and 'quarterLength' not in keywords: self.duration = duration.Duration(0) if self.chordKind or self.chordKindStr: self._updatePitches() # PRIVATE METHODS # def _adjustOctaves(self, pitches): if not isinstance(pitches, list): pitches = list(pitches) # do this for all ninth, thirteenth, and eleventh chords # this must be done to get octave spacing right # possibly rewrite figured bass function with this integrated? ninths = ['dominant-ninth', 'major-ninth', 'minor-ninth'] elevenths = ['dominant-11th', 'major-11th', 'minor-11th'] thirteenths = ['dominant-13th', 'major-13th', 'minor-13th'] if self.chordKind in ninths: pitches[1] = pitch.Pitch(pitches[1].name + str(pitches[1].octave + 1)) elif self.chordKind in elevenths: pitches[1] = pitch.Pitch(pitches[1].name + str(pitches[1].octave + 1)) pitches[3] = pitch.Pitch(pitches[3].name + str(pitches[3].octave + 1)) elif self.chordKind in thirteenths: pitches[1] = pitch.Pitch(pitches[1].name + str(pitches[1].octave + 1)) pitches[3] = pitch.Pitch(pitches[3].name + str(pitches[3].octave + 1)) pitches[5] = pitch.Pitch(pitches[5].name + str(pitches[5].octave + 1)) else: return pitches c = chord.Chord(pitches) c = c.sortDiatonicAscending() return list(c.pitches) def _adjustPitchesForChordStepModifications( self, pitches: t.Iterable[pitch.Pitch] ) -> list[pitch.Pitch]: ''' degree-value element: indicates degree in chord, positive integers only degree-alter: indicates semitone alteration of degree, positive and negative integers only degree-type: `add`, `alter`, or `subtract`: if `add`: degree-alter is relative to a dominant chord (major and perfect intervals except for a minor seventh) if `alter` or `subtract`: degree-alter is relative to degree already in the chord based on its kind element FROM XML DOCUMENTATION The degree element is used to add, alter, or subtract individual notes in the chord. The degree-value element is a number indicating the degree of the chord (1 for the root, 3 for third, etc). The degree-alter element is like the alter element in notes: 1 for sharp, -1 for flat, etc. The degree-type element can be `add`, `alter`, or `subtract`. If the degree-type is `alter` or `subtract`, the degree-alter is relative to the degree already in the chord based on its kind element. If the degree-type is `add`, the degree-alter is relative to a dominant chord (major and perfect intervals except for a minor seventh). The print-object attribute can be used to keep the degree from printing separately when it has already taken into account in the text attribute of the kind element. The plus-minus attribute is used to indicate if plus and minus symbols should be used instead of sharp and flat symbols to display the degree alteration; it is `no` by default. The degree-value and degree-type text attributes specify how the value and type of the degree should be displayed. A harmony of kind "other" can be spelled explicitly by using a series of degree elements together with a root. ''' from music21 import scale pitches = list(pitches) chordStepModifications = self.chordStepModifications if chordStepModifications is None: return pitches rootPitch = self.root() sc = scale.MajorScale(rootPitch) def typeAdd(hD): ''' change the pitches list based on this chordStepModification, adding a pitch ''' pitchToAppend = sc.pitchFromDegree(hD.degree, rootPitch) if hD.interval and hD.interval.semitones != 0: # added degrees are relative to dominant chords, which have all major degrees # except for the seventh which is minor, thus the transposition down one half step. # Don't do this for flatted transformations: # C7addb7 is a redundancy, not a double-flatted seventh. if ( hD.degree == 7 and hD.interval.semitones > 0 and self.chordKind is not None and self.chordKind != '' ): pitchToAppend = pitchToAppend.transpose(-1) pitchToAppend = pitchToAppend.transpose(hD.interval) if hD.degree >= 7: pitchToAppend.octave = pitchToAppend.octave + 1 degrees = self._degreesList if str(hD.degree) in degrees: for p in pitches: if sc.getScaleDegreeFromPitch(p) == hD.degree: pitches.remove(p) pitches.append(pitchToAppend) else: pitches.append(pitchToAppend) # # for now I won't worry about the octave of the added note # # if self.bass() is not None: # # p = sc.pitchFromDegree(hD.degree, self.bass()) # # else: # # p = sc.pitchFromDegree(hD.degree, self.root()) # if hD.degree == 7 and self.chordKind is not None and self.chordKind != '': # # don't know why anyone would want # # to add a seventh to a dominant chord already # # however, according to documentation # # added degrees are relative to dominant chords, which have all major degrees # # except for the seventh which is minor, thus the transposition down # # one half step # p = p.transpose(-1) # self._degreesList.append('-7') # # degreeForList = '-7' # else: # self._degreesList.append(hD.degree) # # degreeForList = str(hD.degree) # # adjust the added pitch by degree-alter interval # if hD.interval: # p = p.transpose(hD.interval) # if hD.degree >= 7: # p.octave = p.octave + 1 # pitches.append(p) def typeSubtract(hD): ''' change the pitches list based on this chordStepModification, removing a pitch ''' degrees = self._degreesList if not degrees: return pitchFound = False for p, degree in zip(pitches, degrees): degree = degree.replace('-', '') degree = degree.replace('#', '') degree = degree.replace('A', '') # A is for 'Altered' if hD.degree == int(degree): pitches.remove(p) pitchFound = True for degreeString in self._degreesList: if str(hD.degree) in degreeString: self._degreesList.remove(degreeString) break # if hD.degree not in string, # should we throw an exception???? for now yes, but maybe later we # will be more lenient. if not pitchFound: raise ChordStepModificationException( f'Degree not in specified chord: {hD.degree}') def typeAlter(hD): ''' alter ''' pitchFound = False degrees = self._degreesList for p, degree in zip(pitches, degrees): degree = degree.replace('-', '') degree = degree.replace('#', '') degree = degree.replace('A', '') # A is for 'Altered' if hD.degree == int(degree): # transpose by semitones (positive for up, negative for down) p = p.transpose(hD.interval, inPlace=True) pitchFound = True # for degreeString in self._degreesList: # if str(hD.degree) in degreeString: # self._degreesList = self._degreesList.replace( # degreeString, ('A' + str(hD.degree))) # # the 'A' stands for altered # break # # if hD.degree not in string: # # should we throw an exception???? for now yes, but maybe later we should. if not pitchFound: raise ChordStepModificationException( f'Degree not in specified chord: {hD.degree}') # main routines for chordStepModification in chordStepModifications: if chordStepModification.modType == 'add': typeAdd(chordStepModification) elif chordStepModification.modType == 'subtract': typeSubtract(chordStepModification) elif chordStepModification.modType == 'alter': try: typeAlter(chordStepModification) except ChordStepModificationException: # fix it in place chordStepModification.modType = 'add' typeAdd(chordStepModification) return pitches def _parseAddAlterSubtract(self, remaining: str, modType: str) -> str: ''' Removes and parses the first instance of a given `modType` such as 'add', 'alter', 'omit', or 'subtract'. Returns the unparsed remainder. >>> cs = harmony.ChordSymbol() >>> cs._parseAddAlterSubtract('add#9omit5', 'add') 'omit5' >>> cs.chordStepModifications [>] ''' degree: str = '' alter: int = 0 startIndex: int = remaining.index(modType) + len(modType) # Remove modType remaining = remaining[startIndex:] if remaining[:1] == 'b': alter = -1 remaining = remaining[1:] elif remaining[:1] == '#': alter = 1 remaining = remaining[1:] # 11, 13, etc. if remaining[:2].isnumeric(): degree = remaining[:2] remaining = remaining[2:] # 9, 6, 4, etc. elif remaining[0].isnumeric(): degree = remaining[0] remaining = remaining[1:] if degree: if modType == 'omit': modType = 'subtract' self.addChordStepModification( ChordStepModification(modType, int(degree), alter), updatePitches=False) return remaining def _getKindFromShortHand(self, sH): originalsH = sH if 'add' in sH: sH = sH[0:sH.index('add')] if 'alter' in sH: sH = sH[0:sH.index('alter')] if 'omit' in sH: sH = sH[0:sH.index('omit')] if 'subtract' in sH: sH = sH[0:sH.index('subtract')] if '#' in sH and sH[sH.index('#') + 1].isdigit(): sH = sH[0:sH.index('#')] if ('b' in sH and sH.index('b') < len(sH) - 1 and sH[sH.index('b') + 1].isdigit() and 'ob9' not in sH and 'øb9' not in sH): sH = sH[0:sH.index('b')] for chordKind in CHORD_TYPES: for charString in getAbbreviationListGivenChordType(chordKind): if sH == charString: self.chordKind = chordKind return originalsH[len(sH):] return originalsH def _hasPitchAboveC4(self, pitches): for p in pitches: if p.diatonicNoteNum > 30: # if there are pitches above middle C, bump the octave down return True return False def _hasPitchBelowA1(self, pitches): for p in pitches: if p.diatonicNoteNum < 13: # anything below this is just obnoxious return True return False def _notationString(self): ''' returns NotationString of ChordSymbolObject which dictates which scale degrees and how those scale degrees are altered in this chord. >>> h = harmony.ChordSymbol('F-dim7') >>> h._notationString() '1,-3,-5,--7' ''' notationString = '' kind = self.chordKind if kind in CHORD_ALIASES: kind = CHORD_ALIASES[kind] if kind in CHORD_TYPES: notationString = getNotationStringGivenChordType(kind) else: notationString = '' degrees = notationString.replace(',', ' ') self._degreesList = degrees.split() return notationString def _parseFigure(self) -> None: ''' Translate the figure string (regular expression) into a meaningful Harmony object by identifying the root, bass, inversion, kind, and kindStr. ''' if self.figure == 'Chord Symbol Cannot Be Identified': return # remove spaces from prelim Figure prelimFigure = self.figure prelimFigure = re.sub(r'\s', '', prelimFigure) # Get Root: if ',' in prelimFigure: root = prelimFigure[0:prelimFigure.index(',')] st = prelimFigure.replace(',', '') st = st.replace(root, '') prelimFigure = prelimFigure.replace(',', '') else: m1 = re.match(r'[A-Ga-g][#-]*', prelimFigure) # match not case-sensitive, if m1: root = m1.group() # remove the root and bass from the string and any additions/omissions/alterations/ st = prelimFigure.replace(m1.group(), '', 1) else: raise ValueError(f'Chord {prelimFigure} does not begin ' + 'with a valid root note.') if root: self.root(pitch.Pitch(root)) # Get optional Bass: m2 = re.search(r'/[A-Ga-g][#-]*', prelimFigure) # match not case-sensitive remaining = st if m2: bass = m2.group() bass = bass.replace('/', '') self.bass(bass, allow_add=True) # remove the root and bass from the string remaining = st.replace(m2.group(), '') st = self._getKindFromShortHand(remaining) ALTER_TYPES = ('add', 'alter', 'omit', 'subtract') searchStart: int = 1000 # not -1 for the sake of min(), below for alterType in ALTER_TYPES: try: searchStart = min(remaining.index(alterType), searchStart) except ValueError: pass searchStringForAlterTypes: str = remaining[searchStart:] substring: str = '' i = 0 while searchStringForAlterTypes and i < len(searchStringForAlterTypes): for char in searchStringForAlterTypes: i += 1 if char.isalpha(): substring += char if substring in ALTER_TYPES: searchStringForAlterTypes = self._parseAddAlterSubtract( searchStringForAlterTypes, substring) substring = '' i = 0 break st = st.replace(',', '') # Unsafe to proceed until every alterType and anything following # is stripped from 'st' for alterType in ALTER_TYPES: if alterType in st: st = st[:st.index(alterType)] if 'b' in st or '#' in st: splitter = re.compile('([b#]+[^b#]+)') alterations = splitter.split(st) else: alterations = [st] indexes = [] altCopy = [] for itemString in alterations: if not itemString: continue justInts = itemString.replace('b', '') justInts = justInts.replace('#', '') try: justInts = int(justInts) except ValueError as ve: raise ValueError( f'Invalid chord abbreviation {st!r}; see ' + 'music21.harmony.CHORD_TYPES for valid ' + 'abbreviations or specify all alterations.' ) from ve if justInts > 20: # MSC: what is this doing? skipNext = False i = 0 charString = '' for char in itemString: if not skipNext: if char == '1': indexes.append(itemString[i] + itemString[i + 1]) skipNext = True elif char in ('b', '#'): charString = charString + char else: charString = charString + char indexes.append(charString) charString = '' else: skipNext = False i = i + 1 else: altCopy.append(itemString) for item in indexes: altCopy.append(item) alterations = altCopy degrees = [] for alteration in alterations: if alteration != '': if 'b' in alteration: semiToneAlter = -1 * alteration.count('b') else: semiToneAlter = alteration.count('#') m3 = re.search(r'[1-9]+', alteration) if m3: degrees.append([int(m3.group()), semiToneAlter]) for degree, alterBy in degrees: self.addChordStepModification( ChordStepModification('add', degree, alterBy), updatePitches=False) def _updatePitches(self): ''' TODO: EXTREMELY SLOW! Calculate the pitches in the chord symbol and update all associated variables, including bass, root, inversion and chord: >>> CS = harmony.ChordSymbol >>> [str(pi) for pi in CS(root='C', bass='E', kind='major').pitches] ['E3', 'G3', 'C4'] >>> [str(pi) for pi in CS(root='C', bass='G', kind='major').pitches] ['G2', 'C3', 'E3'] >>> [str(pi) for pi in CS(root='C', kind='minor').pitches] ['C3', 'E-3', 'G3'] >>> [str(pi) for pi in CS(root='C', bass='B', kind='major-ninth').pitches] ['B2', 'C3', 'D3', 'E3', 'G3'] >>> [str(pi) for pi in CS(root='D', bass='F', kind='minor-seventh').pitches] ['F3', 'A3', 'C4', 'D4'] Note that this ChordSymbol creates what looks like a B- minor-seventh chord in first inversion, but is considered to be a D- chord in root position: >>> dFlatMaj6 = CS('D-6') >>> [str(pi) for pi in dFlatMaj6.pitches] ['D-3', 'F3', 'A-3', 'B-3'] >>> dFlatMaj6.root() >>> dFlatMaj6.inversion() 0 OMIT_FROM_DOCS >>> CS('E7omit3').root().nameWithOctave 'E3' >>> CS('E7omit5/G#').bass().nameWithOctave 'G#2' >>> CS('E9omit5/G#').root().nameWithOctave 'E3' >>> CS('E11omit3').root().nameWithOctave 'E2' ''' if 'root' not in self._overrides or 'bass' not in self._overrides or self.chordKind is None: return from music21.figuredBass import realizerScale # create figured bass scale with root as scale scaleInitTuple = (self._overrides['root'].name, 'major') if scaleInitTuple in realizerScaleCache: fbScale = realizerScaleCache[scaleInitTuple] else: fbScale = realizerScale.FiguredBassScale(self._overrides['root'], 'major') realizerScaleCache[scaleInitTuple] = fbScale # render in the 3rd octave by default self._overrides['root'].octave = 3 self._overrides['bass'].octave = 3 if self._notationString(): pitches = fbScale.getSamplePitches(self._overrides['root'], self._notationString()) # remove duplicated bass note due to figured bass method. pitches.pop(0) else: pitches = [] pitches.append(self._overrides['root']) if self._overrides['bass'] not in pitches: pitches.append(self._overrides['bass']) pitches = self._adjustOctaves(pitches) if self._overrides['root'].name != self._overrides['bass'].name: inversionNum = self.inversion() if not self.inversionIsValid(inversionNum): # there is a bass, yet no normal inversion was found: must be added note inversionNum = None # arbitrary octave, must be below root, # which was arbitrarily chosen as 3 above self._overrides['bass'].octave = 2 pitches.append(self._overrides['bass']) else: self.inversion(None, transposeOnSet=False) inversionNum = None pitches = self._adjustPitchesForChordStepModifications(pitches) if inversionNum not in (0, None): for p in pitches[0:inversionNum]: p.octave = p.octave + 1 # Repeat if 9th/11th/13th chord in 4th inversion or greater if inversionNum > 3: p.octave = p.octave + 1 # if after bumping up the octaves, there are still pitches below bass pitch # bump up their octaves # bassPitch = pitches[inversionNum] # self.bass(bassPitch) for p in pitches: if p.diatonicNoteNum < self._overrides['bass'].diatonicNoteNum: p.octave = p.octave + 1 while self._hasPitchAboveC4(pitches): for thisPitch in pitches: thisPitch.octave -= 1 # but if this has created pitches below lowest note (the A 3 octaves below middle C) # on a standard piano, we're going to have to bump all the octaves back up while self._hasPitchBelowA1(pitches): for thisPitch in pitches: thisPitch.octave += 1 self.pitches = tuple(pitches) self.sortDiatonicAscending(inPlace=True) # set overrides to be pitches in the harmony # self._overrides = {} # JTW: was wiping legit overrides such as root=C from 'C6' self.bass(self.bass(), allow_add=True) self.root(self.root()) # PUBLIC METHODS # def findFigure(self): ''' Return the chord symbol figure associated with this chord. This method tries to deduce what information it can from the provided pitches. >>> h = harmony.ChordSymbol(root='F', bass='D-', kind='Neapolitan') >>> h.figure 'FN6/D-' Thanks to Norman Schmidt for code sample and helping fix a bug >>> foster = corpus.parse('leadsheet/fosterBrownHair.xml') >>> foster = foster.parts[0].getElementsByClass(stream.Measure) >>> for m in foster[12:17]: ... c = m.getElementsByClass(harmony.ChordSymbol) ... if c: ... ch = c[0].figure ... print(ch.replace('-', 'b')) ... else: ... print('n.c.') F G7 C C C Thanks to David Bolton for catching the bugs tested below: >>> h1 = harmony.ChordSymbol('C7 b9') >>> for x in h1.pitches: ... x ... >>> h2 = harmony.ChordSymbol('C/B- add 2') >>> for x in h2.pitches: ... x ... OMIT_FROM_DOCS >>> from xml.etree.ElementTree import fromstring as EL >>> MP = musicxml.xmlToM21.MeasureParser() >>> elStr = (r'Cdominant' + ... '9-1' + ... ' add') >>> mxHarmony = EL(elStr) >>> cs = MP.xmlToChordSymbol(mxHarmony) >>> print(cs.figure) C7 add b9 >>> cs.pitches (, , , , ) >>> elStr = (r'Cmajor' + ... 'B-1' + ... '20' + ... ' add') >>> mxHarmony = EL(elStr) >>> cs = MP.xmlToChordSymbol(mxHarmony) >>> print(cs.figure) C/B- add 2 >>> cs.pitches (, , , , ) ''' if self.chordStepModifications or self.chordKind: # there is no hope to determine the chord from pitches # if it's been modified, so we'll just have to try this route: if self.root() is None: raise HarmonyException('Cannot find figure. No root to the chord found', self) figure = self.root().name kind = self.chordKind if kind in CHORD_ALIASES: kind = CHORD_ALIASES[kind] if kind in CHORD_TYPES: figure += getAbbreviationListGivenChordType(kind)[0] if self.bass() is not None: if self.root().name != self.bass().name: figure += '/' + self.bass().name for csMod in self.chordStepModifications: if csMod.interval is not None: numAlter = csMod.interval.semitones if numAlter > 0: s = '#' else: s = 'b' prefix = s * abs(numAlter) figure += ' ' + csMod.modType + ' ' + prefix + str(csMod.degree) else: figure += ' ' + csMod.modType + ' ' + str(csMod.degree) return figure else: # if neither chordKind nor chordStepModifications, best bet is probably to # try to deduce the figure from the chord return chordSymbolFigureFromChord(self) def inversionIsValid(self, inversion): ''' Returns true if the provided inversion exists for the given pitches of the chord. If not, it returns false and the getPitches method then appends the bass pitch to the chord. ''' sevenths = ( 'French', 'German', 'Italian', 'Neapolitan', 'Tristan', 'augmented-seventh', 'diminished-seventh', 'dominant-seventh', 'half-diminished', 'major-minor', 'major-seventh', 'minor-seventh', ) ninths = ( 'dominant-ninth', 'major-ninth', 'minor-ninth', ) elevenths = ( 'dominant-11th', 'major-11th', 'minor-11th', ) thirteenths = ( 'dominant-13th', 'major-13th', 'minor-13th', ) if inversion == 5 and ( self.chordKind in thirteenths or self.chordKind in elevenths ): return True elif inversion == 4 and ( self.chordKind in elevenths or self.chordKind in thirteenths or self.chordKind in ninths ): return True elif inversion == 3 and ( self.chordKind in sevenths or self.chordKind in ninths or self.chordKind in elevenths or self.chordKind in thirteenths ): return True elif (inversion in (2, 1) and self.chordKind != 'pedal'): return True elif inversion is None: return False else: return False def transpose(self: T, value, *, inPlace=False) -> T|None: ''' Overrides :meth:`~music21.chord.Chord.transpose` so that this ChordSymbol's `figure` is appropriately cleared afterward. >>> cs = harmony.ChordSymbol('Am') >>> cs.figure 'Am' >>> cs.transpose(1) >>> cs.transpose(5, inPlace=True) >>> cs >>> cs.figure 'Dm' ''' post = super().transpose(value, inPlace=inPlace) if not inPlace: post.figure = None return post else: self.figure = None return None class NoChord(ChordSymbol): ''' Class representing a special 'no chord' ChordSymbol used to explicitly encode absence of chords. This is especially useful to stop a chord without playing another. >>> from music21.harmony import ChordSymbol, NoChord >>> s = stream.Score() >>> s.repeatAppend(note.Note('C'), 4) >>> s.append(ChordSymbol('C')) >>> s.repeatAppend(note.Note('C'), 4) >>> s.append(NoChord()) >>> s.repeatAppend(note.Note('C'), 4) >>> s = s.makeMeasures() See how the chordSymbol of C stops at offset 8 rather than continuing, thanks to the NoChord object. >>> s = harmony.realizeChordSymbolDurations(s) >>> s.show('text', addEndTimes=True) {0.0 - 0.0} {0.0 - 0.0} {0.0 - 1.0} {1.0 - 2.0} {2.0 - 3.0} {3.0 - 4.0} {4.0 - 8.0} {4.0 - 5.0} {5.0 - 6.0} {6.0 - 7.0} {7.0 - 8.0} {8.0 - 12.0} {8.0 - 9.0} {9.0 - 10.0} {10.0 - 11.0} {11.0 - 12.0} {12.0 - 12.0} >>> c_major = s.getElementsByClass(ChordSymbol).first() >>> c_major.duration >>> c_major.offset 4.0 Other text than the default of 'N.C.' can be given: >>> nc2 = NoChord('NC') >>> nc2 >>> nc2.pitches () Note that even if the text is a valid chord abbreviation, no pitches are generated. This feature may be useful for adding the appearance of ChordSymbols in a piece without having them be realized. >>> nc2 = NoChord('C7') >>> nc2 >>> nc2.pitches () ''' def __init__( self, figure: str|None = None, kind: str|None = 'none', kindStr: str|None = None, **keywords ): super().__init__(figure, kind=kind, kindStr=kindStr or figure or 'N.C.', **keywords) if self._figure is None: self._figure = self.chordKindStr def root(self, newroot=None, *, find=None): # Ignore newroot, and set find to "False" to always return None return None def bass(self, newbass=None, *, find=None, allow_add=False): # Ignore newbass, and set find to "False" to always return None return None def _parseFigure(self): # do nothing, everything is already set. return def transpose(self: NCT, _value, *, inPlace=False) -> NCT|None: ''' Overrides :meth:`~music21.chord.Chord.transpose` to do nothing. >>> nc = harmony.NoChord() >>> nc.figure 'N.C.' >>> nc.transpose(8, inPlace=True) >>> nc.figure 'N.C.' ''' if not inPlace: return copy.deepcopy(self) else: return None # ------------------------------------------------------------------------------ def realizeChordSymbolDurations(piece): ''' Returns music21 stream with duration attribute of chord symbols correctly set. Duration of chord symbols is based on the surrounding chord symbols; The chord symbol continues duration until another chord symbol is located or the piece ends. >>> s = stream.Score() >>> s.append(harmony.ChordSymbol('C')) >>> s.repeatAppend(note.Note('C'), 4) >>> s.append(harmony.ChordSymbol('C')) >>> s.repeatAppend(note.Note('C'), 4) >>> s = s.makeMeasures() >>> harmony.realizeChordSymbolDurations(s).show('text') {0.0} {0.0} {0.0} {0.0} {1.0} {2.0} {3.0} {4.0} {4.0} {5.0} {6.0} {7.0} {8.0} If only one chord symbol object is present: >>> s = stream.Score() >>> s.append(harmony.ChordSymbol('C')) >>> s.repeatAppend(note.Note('C'), 4) >>> s = s.makeMeasures() >>> harmony.realizeChordSymbolDurations(s).show('text') {0.0} {0.0} {0.0} {0.0} {1.0} {2.0} {3.0} {4.0} If a ChordSymbol object exists followed by many notes, duration represents all those notes (how else can the computer know to end the chord? if there's no chord following it other than end the chord at the end of the piece?). >>> s = stream.Score() >>> s.repeatAppend(note.Note('C'), 4) >>> s.append(harmony.ChordSymbol('C')) >>> s.repeatAppend(note.Note('C'), 8) >>> s = s.makeMeasures() >>> harmony.realizeChordSymbolDurations(s).show('text') {0.0} {0.0} {0.0} {1.0} {2.0} {3.0} {4.0} {4.0} {5.0} {6.0} {7.0} {8.0} {9.0} {10.0} {11.0} {12.0} ''' pf = piece.flatten() onlyChords = pf.getElementsByClass(ChordSymbol).stream() first = True lastChord = None if len(onlyChords) > 1: for cs in onlyChords: if first: first = False lastChord = cs continue else: qlDiff = pf.elementOffset(cs) - pf.elementOffset(lastChord) lastChord.duration.quarterLength = qlDiff if onlyChords.index(cs) == (len(onlyChords) - 1): cs.duration.quarterLength = pf.highestTime - pf.elementOffset(cs) lastChord = cs return pf elif len(onlyChords) == 1: onlyChords[0].duration.quarterLength = pf.highestTime - pf.elementOffset(onlyChords[0]) return pf else: return piece # ------------------------------------------------------------------------------ class Test(unittest.TestCase): def testChordAttributes(self): from music21 import harmony cs = harmony.ChordSymbol('Cm') self.assertEqual(str(cs), '') self.assertEqual( str(cs.pitches), '(, , )') self.assertEqual(str(cs.bass()), 'C3') self.assertTrue(cs.isConsonant()) def testBasic(self): from music21 import harmony h = harmony.Harmony() hd = harmony.ChordStepModification('add', 4) h.addChordStepModification(hd) self.assertEqual(len(h.chordStepModifications), 1) def testChordKindSetting(self): from music21 import harmony cs = harmony.ChordSymbol() cs.root('E-') cs.bass('B-', allow_add=True) cs.inversion(2, transposeOnSet=False) cs.romanNumeral = 'I64' cs.chordKind = 'major' cs.chordKindStr = 'M' self.assertEqual(repr(cs), '') def testDoubleSharpsEtc(self): # noinspection SpellCheckingInspection cisisdim = chord.Chord(('c##5', 'e#5', 'g#5')) fig = chordSymbolFigureFromChord(cisisdim) self.assertEqual(fig, 'C##dim') def testChordSymbolSetsBassOctave(self): d = ChordSymbol('Cm/E-') root = d.root() self.assertEqual(root.nameWithOctave, 'C4') b = d.bass() self.assertEqual(b.nameWithOctave, 'E-3') def testHarmonyPreservesInversionAndBass(self): ''' Test that bass is preserved even when both bass and inversion are given ''' explicitFm6 = ChordSymbol(root='F', bass='A-', inversion=1, kind='minor') self.assertEqual(explicitFm6.inversion(), 1) self.assertEqual(explicitFm6.bass(find=False).name, 'A-') self.assertEqual(explicitFm6.root(find=False).name, 'F') self.assertLess(explicitFm6.bass(find=False).octave, explicitFm6.root(find=False).octave) def testClassSortOrderHarmony(self): ''' This tests a former bug in getContextByClass because ChordSymbol used to have the same `.classSortOrder` as Note. ''' from music21 import note from music21 import stream cs = ChordSymbol('C') n = note.Note('C') m = stream.Measure(1) m.insert(0, n) m.insert(0, cs) self.assertIs(n.getContextByClass('ChordSymbol'), cs) # check that it works also with append cs = ChordSymbol('C') n = note.Note('C') n.duration.quarterLength = 0 m = stream.Measure(1) m.append(n) m.append(cs) self.assertIs(n.getContextByClass('ChordSymbol'), cs) def testNoChord(self): from music21 import harmony nc = harmony.NoChord() self.assertEqual('none', nc.chordKind) self.assertEqual('N.C.', nc.chordKindStr) self.assertEqual('N.C.', nc.figure) nc = harmony.NoChord('NC') self.assertEqual('none', nc.chordKind) self.assertEqual('NC', nc.chordKindStr) self.assertEqual('NC', nc.figure) nc = harmony.NoChord('None') self.assertEqual('none', nc.chordKind) self.assertEqual('None', nc.chordKindStr) self.assertEqual('None', nc.figure) nc = harmony.NoChord(kind='none') self.assertEqual('none', nc.chordKind) self.assertEqual('N.C.', nc.chordKindStr) self.assertEqual('N.C.', nc.figure) nc = harmony.NoChord(kindStr='No Chord') self.assertEqual('none', nc.chordKind) self.assertEqual('No Chord', nc.chordKindStr) self.assertEqual('No Chord', nc.figure) nc = harmony.NoChord('NC', kindStr='No Chord') self.assertEqual('none', nc.chordKind) self.assertEqual('No Chord', nc.chordKindStr) self.assertEqual('NC', nc.figure) nc = harmony.NoChord(root='C', bass='E', kind='none') self.assertEqual('N.C.', nc.chordKindStr) self.assertEqual('N.C.', nc.figure) self.assertEqual(str(nc), '') self.assertEqual(0, len(nc.pitches)) self.assertIsNone(nc.root()) self.assertIsNone(nc.bass()) nc._updatePitches() self.assertEqual(0, len(nc.pitches)) def testInvalidRoots(self): from music21 import harmony with self.assertRaises(ValueError) as context: harmony.ChordSymbol('H-7') self.assertEqual( str(context.exception), 'Chord H-7 does not begin with a valid root note.' ) with self.assertRaises(ValueError) as context: # noinspection SpellCheckingInspection harmony.ChordSymbol('Garg7') self.assertEqual( str(context.exception), "Invalid chord abbreviation 'arg7'; see " + 'music21.harmony.CHORD_TYPES for valid ' + 'abbreviations or specify all alterations.' ) def testInvalidSymbol(self): from music21 import harmony c = chord.Chord(('A#', 'C', 'E')) cs = harmony.chordSymbolFromChord(c) self.assertEqual(cs.figure, 'Chord Symbol Cannot Be Identified') def testRegexEdgeCases(self): cs = ChordSymbol('FFr+6') self.assertEqual([p.name for p in cs.pitches], ['F', 'G', 'B', 'D-']) cs = ChordSymbol('dadd6') self.assertEqual([p.name for p in cs.pitches], ['D', 'F#', 'A', 'B']) cs = ChordSymbol('atristan') self.assertEqual([p.name for p in cs.pitches], ['A', 'B#', 'D#', 'F##']) def runTestOnChord(self, xmlString, figure, pitches): ''' Run a series of tests on the given chord. xmlString: an XML harmony object figure: the equivalent figure representation pitches: the list of pitches of the chord ''' from xml.etree.ElementTree import fromstring as EL from music21 import musicxml pitches = tuple(pitch.Pitch(p) for p in pitches) MP = musicxml.xmlToM21.MeasureParser() mxHarmony = EL(xmlString) cs1 = MP.xmlToChordSymbol(mxHarmony) cs2 = ChordSymbol(cs1.figure) cs3 = ChordSymbol(figure) self.assertEqual(pitches, cs1.pitches) self.assertEqual(pitches, cs2.pitches) self.assertEqual(pitches, cs3.pitches) kind1 = cs1.chordKind kind2 = cs2.chordKind kind3 = cs3.chordKind if kind1 in CHORD_ALIASES: kind1 = CHORD_ALIASES[kind1] if kind2 in CHORD_ALIASES: kind2 = CHORD_ALIASES[kind2] if kind3 in CHORD_ALIASES: kind3 = CHORD_ALIASES[kind3] self.assertEqual(kind1, kind2) self.assertEqual(kind1, kind3) self.assertEqual(cs1.root(), cs2.root()) self.assertEqual(cs1.root(), cs3.root()) self.assertEqual(cs1.bass(), cs2.bass()) self.assertEqual(cs1.bass(), cs3.bass()) def testChordWithBass(self): xmlString = ''' A dominant 3 G ''' figure = 'A7/G' pitches = ('G2', 'A2', 'C#3', 'E3') self.runTestOnChord(xmlString, figure, pitches) def testChordFlatSharpInFigure(self): # Octave placement of this A2 neither great nor intolerable pitches = ('G2', 'A2', 'B2', 'D#3', 'F3') figure = 'G+9' cs = ChordSymbol(figure) self.assertEqual(cs.pitches, tuple(pitch.Pitch(p) for p in pitches)) pitches = ('G2', 'B2', 'D#3', 'F3', 'A3') figure = 'G9#5' cs = ChordSymbol(figure) self.assertEqual(cs.pitches, tuple(pitch.Pitch(p) for p in pitches)) pitches = ('A2', 'C3', 'E3', 'G#3') pitches = tuple(pitch.Pitch(p) for p in pitches) self.assertEqual(pitches, ChordSymbol('AmM7').pitches) self.assertEqual(pitches, ChordSymbol('Aminmaj7').pitches) pitches = ('A1', 'C2', 'E2', 'G#3') pitches = tuple(pitch.Pitch(p) for p in pitches) self.assertEqual(pitches, ChordSymbol('Am#7').pitches) pitches = ('C2', 'F2', 'G2', 'B-3') pitches = tuple(pitch.Pitch(p) for p in pitches) self.assertEqual(pitches, ChordSymbol('Csusaddb7').pitches) def testRootBassParsing(self): ''' This tests a bug where the root and bass were wrongly parsed, since the matched root and bass were globally removed from figure, and not only where matched. ''' xmlString = ''' E dominant E -1 ''' figure = 'E7/E-' pitches = ('E-2', 'E3', 'G#3', 'B3', 'D4') self.runTestOnChord(xmlString, figure, pitches) def testChordStepBass(self): ''' This tests a bug where the chord modification (add 2) was placed at a wrong octave, resulting in a D bass instead of the proper E. ''' xmlString = ''' C major E 2 0 add ''' figure = 'C/E add 2' pitches = ('E3', 'G3', 'C4', 'D4') self.runTestOnChord(xmlString, figure, pitches) def testSusBass(self): ''' This tests a bug where the bass addition was considered as the fifth inversion in suspended chords. Now, this is considered as a non-valid inversion, and the bass is simply added before the root. ''' from xml.etree.ElementTree import fromstring as EL from music21 import musicxml pitches = ('G2', 'D3', 'G3', 'A3') pitches = tuple(pitch.Pitch(p) for p in pitches) xmlString = ''' D suspended-fourth G ''' MP = musicxml.xmlToM21.MeasureParser() mxHarmony = EL(xmlString) cs1 = MP.xmlToChordSymbol(mxHarmony) cs2 = ChordSymbol(cs1.figure) cs3 = ChordSymbol('Dsus/G') self.assertEqual(pitches, cs1.pitches) self.assertEqual(pitches, cs2.pitches) self.assertEqual(pitches, cs3.pitches) def testBassNotInChord(self): from xml.etree.ElementTree import fromstring as EL from music21 import musicxml pitches = ('E-3', 'E3', 'G3', 'C4') pitches = tuple(pitch.Pitch(p) for p in pitches) xmlString = ''' C major E- ''' MP = musicxml.xmlToM21.MeasureParser() mxHarmony = EL(xmlString) cs1 = MP.xmlToChordSymbol(mxHarmony) cs2 = ChordSymbol(cs1.figure) cs3 = ChordSymbol('C/E-') self.assertEqual(pitches, cs1.pitches) self.assertEqual(pitches, cs2.pitches) self.assertEqual(pitches, cs3.pitches) # There was a bug where the bass was E3, because E-3 was assumed to be # in the chord. self.assertEqual('E-3', cs1.bass().nameWithOctave) def testSus2Bass(self): from xml.etree.ElementTree import fromstring as EL from music21 import musicxml pitches = ('E3', 'G3', 'C4', 'D4') pitches = tuple(pitch.Pitch(p) for p in pitches) xmlString = ''' C suspended-second E ''' MP = musicxml.xmlToM21.MeasureParser() mxHarmony = EL(xmlString) cs1 = MP.xmlToChordSymbol(mxHarmony) cs2 = ChordSymbol(cs1.figure) cs3 = ChordSymbol('Csus2/E') self.assertEqual('E3', cs1.bass().nameWithOctave) self.assertEqual(pitches, cs1.pitches) self.assertEqual(pitches, cs2.pitches) self.assertEqual(pitches, cs3.pitches) def testNinth(self): ''' This tests a bug in _adjustOctaves. ''' xmlString = ''' D minor-ninth ''' pitches = ('D2', 'F2', 'A2', 'C3', 'E3') figure = 'Dm9' self.runTestOnChord(xmlString, figure, pitches) def testInversion(self): from xml.etree.ElementTree import fromstring as EL from music21 import musicxml xmlString = ''' C major 1 ''' pitches = ('E2', 'G2', 'C3') pitches = tuple(pitch.Pitch(p) for p in pitches) MP = musicxml.xmlToM21.MeasureParser() mxHarmony = EL(xmlString) cs1 = MP.xmlToChordSymbol(mxHarmony) cs2 = ChordSymbol('C/E') self.assertEqual(1, cs1.inversion()) self.assertEqual(1, cs2.inversion()) pitches = ('E3', 'G3', 'C4') pitches = tuple(pitch.Pitch(p) for p in pitches) self.assertEqual(cs1.pitches, pitches) self.assertEqual(cs2.pitches, pitches) self.assertEqual(cs1.root(), cs2.root()) self.assertEqual(cs1.bass(), cs2.bass()) def testChordWithoutKind(self): cs = ChordSymbol(root='C', bass='E') self.assertEqual(1, cs.inversion()) self.assertEqual('C4', str(cs.root())) self.assertEqual('E3', str(cs.bass())) def testChordStepFromFigure(self): xmlString = ''' G dominant 5 0 subtract 9 -1 add 9 1 add 11 1 add 13 -1 add ''' figure = 'G7 subtract 5 add b9 add #9 add #11 add b13' pitches = ('G2', 'B2', 'F3', 'A-3', 'A#3', 'C#4', 'E-4') self.runTestOnChord(xmlString, figure, pitches) figure = 'G7 subtract5 addb9 add#9 add#11 addb13' self.runTestOnChord(xmlString, figure, pitches) figure = 'G7subtract5addb9add#9add#11addb13' self.runTestOnChord(xmlString, figure, pitches) ######### xmlString = ''' C dominant 9 -1 add ''' figure = 'C7 b9' pitches = ('C3', 'E3', 'G3', 'B-3', 'D-4') self.runTestOnChord(xmlString, figure, pitches) figure = 'C7 add b9' self.runTestOnChord(xmlString, figure, pitches) # Test alter cs = ChordSymbol('A7 alter #5') self.assertEqual('(, , , ' ')', str(cs.pitches)) ######### xmlString = ''' A dominant 5 1 alter 9 1 add 11 1 add ''' figure = 'A7 alter #5 add #9 add #11' pitches = ('A2', 'C#3', 'E#3', 'G3', 'B#3', 'D#4') self.runTestOnChord(xmlString, figure, pitches) def testExpressSusUsingAlterations(self): ch1 = ChordSymbol('F7 add 4 subtract 3') ch2 = ChordSymbol('F7sus4') self.assertEqual(ch1.pitches, ch2.pitches) def testDoubledCharacters(self): ch1 = ChordSymbol('Co omit5') ch2 = ChordSymbol('Cdim omit5') self.assertEqual(ch1.pitches, ch2.pitches) def x_testPower(self): ''' power chords should not have inversions ''' pitches = ('E2', 'A2', 'E3') pitches = tuple(pitch.Pitch(p) for p in pitches) xmlString = ''' A power E ''' figure = 'Apower/E' self.runTestOnChord(xmlString, figure, pitches) def testSingleChordSymbol(self): ''' Test an edge case where a Stream contains only one ChordSymbol at the highest offset: should still have a nonzero duration if there is a subsequent highest time. ''' from music21 import note from music21 import stream m = stream.Measure() # NB: no barline! cs = ChordSymbol('A7') m.insert(0, note.Note(type='whole')) m.insert(1.0, cs) realizeChordSymbolDurations(m) self.assertEqual(cs.quarterLength, 3.0) def testUpdatePitchesFalse(self): bass_note = pitch.Pitch('C3') h = Harmony(bass=bass_note, updatePitches=False) # No other pitches are created self.assertEqual(h.pitches, (bass_note,)) class TestExternal(unittest.TestCase): def testReadInXML(self): from music21 import harmony from music21 import corpus from music21 import stream testFile = corpus.parse('leadSheet/fosterBrownHair.xml') # testFile.show('text') testFile = harmony.realizeChordSymbolDurations(testFile) # testFile.show() chordSymbols = testFile.flatten().getElementsByClass(harmony.ChordSymbol) s = stream.Stream() for cS in chordSymbols: cS.writeAsChord = False s.append(cS) # csChords = s.flatten().getElementsByClass(chord.Chord) # s.show() # self.assertEqual(len(csChords), 40) def testChordRealization(self): from music21 import harmony from music21 import corpus from music21 import note from music21 import stream # There is a test file under demos called ComprehensiveChordSymbolsTestFile.xml # that should contain a complete iteration of tests of chord symbol objects # this test makes sure that no error exists, and checks that 57 chords were # created out of that file. Feel free to add to file if you find missing # tests, and adjust 57 accordingly testFile = corpus.parse('demos/ComprehensiveChordSymbolsTestFile.xml') testFile = harmony.realizeChordSymbolDurations(testFile) chords = testFile.flatten().getElementsByClass(harmony.ChordSymbol) # testFile.show() s = stream.Stream() # i = 0 for x in chords: # print(x.pitches) x.quarterLength = 0 s.insert(x.offset, x) # i += 4 # # x.show() s.makeRests(fillGaps=True, inPlace=True) s.append(note.Rest(quarterLength=4)) unused_csChords = s.flatten().getElementsByClass(chord.Chord) # self.assertEqual(len(csChords), 57) # s.show() # s.show('text') def testALLChordKinds(self): notes = ['A', 'B', 'C', 'D', 'E', 'F', 'G'] mod = ['', '-', '#'] for n in notes: for m in mod: for unused_key, val in CHORD_TYPES.items(): # example val = ['1,-3,5,6', ['m6', 'min6']] for harmony_type in val[1]: symbol = n + m + harmony_type ChordSymbol(symbol) # def labelChordSymbols(self): # ''' # A very rough sketch of code to label the chord symbols in a bach # chorale (in response to a post to the music21 list asking if this is # possible). # ''' # from music21.alpha.theoryAnalysis import theoryAnalyzer # from music21 import harmony, corpus # # score = corpus.parse('bach/bwv380') # excerpt = score.measures(2, 3) # # # remove passing and/or neighbor tones? # analyzer = theoryAnalyzer.Analyzer() # analyzer.removePassingTones(excerpt) # analyzer.removeNeighborTones(excerpt) # # slices = analyzer.getVerticalities(excerpt) # for vs in slices: # x = harmony.chordSymbolFigureFromChord(vs.getChord()) # if x != 'Chord Symbol Cannot Be Identified': # vs.lyric = x.replace('-', 'b') # print(x.replace('-', 'b')) # ------------------------------------------------------------------------------ _DOC_ORDER = [Harmony, chordSymbolFigureFromChord, ChordSymbol, ChordStepModification] if __name__ == '__main__': import music21 music21.mainTest(Test) # , runTest='testChordStepBass')