def viio65ResolutionExample():
'''
For a fully diminished seventh chord resolving to the tonic, the resolution chord
can contain either a doubled third (standard resolution) or a doubled tonic (alternate
resolution), depending on whether the third of the diminished chord rises or falls.
The user can control this in a Rules object by modifying
:attr:`~music21.figuredBass.rules.Rules.doubledRootInDim7`.
However, when resolving a diminished 6,5, the third is found in the bass and the
proper resolution is determined in context, regardless of user preference.
The following shows both cases involving a diminished 6,5. The resolution of the
first diminished chord has a doubled D, while that of the second has a doubled F#.
Notice that the resolution of the first involves a diminished fifth (E, Bb) going
to a perfect fifth (D, A).
>>> from music21.figuredBass import examples
>>> fbLine = examples.viio65ResolutionExample()
>>> fbRealization = fbLine.realize()
>>> #_DOCS_SHOW fbRealization.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_vii65.*
:width: 700
'''
from music21 import converter, key
s = converter.parse("tinyNotation: 4/4 D2 E2_6,b5 D2 E2_6,b5 F#1_6",
makeNotation=False)
s.insert(0, key.Key('D'))
return realizer.figuredBassFromStream(s)
def italianA6ResolutionExample():
'''
The Italian augmented sixth chord (It+6) is the only augmented sixth chord to consist of only three
pitch names, and when represented in four parts, the tonic is doubled. The tonic can resolve up, down or
stay the same, and in four parts, the two tonics always resolve differently, resulting in two equally
acceptable resolutions. An alternate approach to resolving the It+6 chord was taken, such that an It+6
chord could map internally to two different resolutions. Every other special resolution in fbRealizer
consists of a 1:1 mapping of special chords to resolutions.
Here, the It+6 chord is resolving to the dominant, minor tonic, and major tonic, respectively. In the
dominant resolution shown, the tonics (D) are resolving inward, but they can resolve outward as well. In
the minor tonic resolution, the higher tonic is resolving up to F, and the lower tonic remains the same.
In the major tonic resolution, the higher tonic remains the same, while the lower tonic resolves up to the F#.
>>> from music21.figuredBass import examples
>>> from music21.figuredBass import rules
>>> fbLine = examples.italianA6ResolutionExample()
>>> fbRules = rules.Rules()
>>> fbRules.upperPartsMaxSemitoneSeparation = None
>>> fbRules.partMovementLimits.append([1,4])
>>> fbRealization = fbLine.realize(fbRules)
>>> fbRealization.keyboardStyleOutput = False
>>> #_DOCS_SHOW fbRealization.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_it+6.*
:width: 700
'''
from music21 import tinyNotation, key
s = tinyNotation.TinyNotationStream("D4 BB-4_#6,3 AA2_# D4 BB-4_#6,3 AA2_6,4 D4 BB-4_#6,3 AA2_#6,4")
s.insert(0, key.Key('d'))
return realizer.figuredBassFromStream(s)
def augmentedSixthResolutionExample():
"""
This example was retrieved from page 61 of *The Music Theory Handbook* by Marjorie Merryman.
Italian (8,#6,3), French (#6,4,3), German (#6,5,3), and Swiss (#6,#4,3) augmented sixth resolutions to
either the major dominant or the major/minor tonic 6,4 are supported. The first four bars show the
resolutions to the dominant in the order above, while the last bar shows the German augmented sixth
resolving to the tonic.
>>> from music21.figuredBass import examples
>>> fbLine = examples.augmentedSixthResolutionExample()
>>> fbRealization = fbLine.realize()
>>> #_DOCS_SHOW fbRealization.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_a6.*
:width: 700
"""
from music21 import tinyNotation, key
s = tinyNotation.TinyNotationStream(
"D4 BB-4_8,#6,3 AA2_# D4 BB-4_#6,4,3 AA2_# D4 BB-4_#6,5,3 AA2_# D4 BB-4_#6,#4,3 AA2_# D4 BB-4_#6,5,3 AA2_6,4",
"4/4",
)
s.insert(0, key.Key("d"))
return realizer.figuredBassFromStream(s)
def viio65ResolutionExample():
'''
For a fully diminished seventh chord resolving to the tonic, the resolution chord
can contain either a doubled third (standard resolution) or a doubled tonic (alternate
resolution), depending on whether the third of the diminished chord rises or falls.
The user can control this in a Rules object by modifying :attr:`~music21.figuredBass.rules.Rules.doubledRootInDim7`.
However, when resolving a diminished 6,5, the third is found in the bass and the
proper resolution is determined in context, regardless of user preference.
The following shows both cases involving a diminished 6,5. The resolution of the
first diminished chord has a doubled D, while that of the second has a doubled F#.
Notice that the resolution of the first involves a diminished fifth (E, Bb) going
to a perfect fifth (D, A).
>>> from music21.figuredBass import examples
>>> fbLine = examples.viio65ResolutionExample()
>>> fbRealization = fbLine.realize()
>>> #_DOCS_SHOW fbRealization.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_vii65.*
:width: 700
'''
from music21 import tinyNotation, key
s = tinyNotation.TinyNotationStream("D2 E2_6,b5 D2 E2_6,b5 F#1_6", "4/4")
s.insert(0, key.Key('D'))
return realizer.figuredBassFromStream(s)
def italianA6ResolutionExample():
'''
The Italian augmented sixth chord (It+6) is the only augmented sixth chord to consist of only three
pitch names, and when represented in four parts, the tonic is doubled. The tonic can resolve up, down or
stay the same, and in four parts, the two tonics always resolve differently, resulting in two equally
acceptable resolutions. An alternate approach to resolving the It+6 chord was taken, such that an It+6
chord could map internally to two different resolutions. Every other special resolution in fbRealizer
consists of a 1:1 mapping of special chords to resolutions.
Here, the It+6 chord is resolving to the dominant, minor tonic, and major tonic, respectively. In the
dominant resolution shown, the tonics (D) are resolving inward, but they can resolve outward as well. In
the minor tonic resolution, the higher tonic is resolving up to F, and the lower tonic remains the same.
In the major tonic resolution, the higher tonic remains the same, while the lower tonic resolves up to the F#.
>>> from music21.figuredBass import examples
>>> from music21.figuredBass import rules
>>> fbLine = examples.italianA6ResolutionExample()
>>> fbRules = rules.Rules()
>>> fbRules.upperPartsMaxSemitoneSeparation = None
>>> fbRules.partMovementLimits.append([1,4])
>>> fbRealization = fbLine.realize(fbRules)
>>> fbRealization.keyboardStyleOutput = False
>>> #_DOCS_SHOW fbRealization.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_it+6.*
:width: 700
'''
from music21 import converter, key
s = converter.parse("tinynotation: D4 BB-4_#6,3 AA2_# D4 BB-4_#6,3 AA2_6,4 D4 BB-4_#6,3 AA2_#6,4", makeNotation=False)
s.insert(0, key.Key('d'))
return realizer.figuredBassFromStream(s)
def twelveBarBlues():
'''
This is a progression in Bb major based on the twelve bar blues. The progression used is:
I | IV | I | I7
IV | IV | I | I7
V7 | IV6 | I | I
>>> from music21.figuredBass import examples
>>> from music21.figuredBass import rules
>>> bluesLine = examples.twelveBarBlues()
>>> #_DOCS_SHOW bluesLine.generateBassLine().show()
.. image:: images/figuredBass/fbExamples_bluesBassLine.*
:width: 700
>>> fbRules = rules.Rules()
>>> fbRules.partMovementLimits = [(1, 4), (2, 12), (3, 12)]
>>> fbRules.forbidVoiceOverlap = False
>>> blRealization = bluesLine.realize(fbRules)
>>> blRealization.getNumSolutions()
2224978
>>> #_DOCS_SHOW blRealization.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_twelveBarBlues.*
:width: 700
'''
from music21 import converter
from music21 import key
s = converter.parse(
"tinynotation: BB-1 E-1 BB-1 BB-1_7 E-1 E-1 BB-1 BB-1_7 F1_7 G1_6 BB-1 BB-1",
makeNotation=False)
s.insert(0, key.Key('B-'))
return realizer.figuredBassFromStream(s)
def exampleD():
'''
This example was a homework assignment for 21M.302: Harmony & Counterpoint II
at MIT in the fall of 2010, taught by Charles Shadle of the MIT Music Program.
>>> from music21.figuredBass import examples
>>> fbLine = examples.exampleD()
>>> #_DOCS_SHOW fbLine.generateBassLine().show()
.. image:: images/figuredBass/fbExamples_bassLineD.*
:width: 700
The following is a realization of fbLine in four parts using the default rules set.
The soprano part is limited to stepwise motion, and the alto and tenor parts are
limited to motions within a perfect octave.
>>> from music21.figuredBass import rules
>>> fbRules = rules.Rules()
>>> fbRules.partMovementLimits = [(1,2),(2,12),(3,12)]
>>> fbRealization1 = fbLine.realize(fbRules)
>>> fbRealization1.getNumSolutions()
1560
>>> #_DOCS_SHOW fbRealization1.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol1D.*
:width: 700
Now, the restriction on voice overlap is lifted, which is common in keyboard-style
figured bass, and fbLine is realized again. Voice overlap can be seen in the fourth
measure.
>>> fbRules.forbidVoiceOverlap = False
>>> fbRealization2 = fbLine.realize(fbRules)
>>> fbRealization2.getNumSolutions()
109006
>>> #_DOCS_SHOW fbRealization2.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol2D.*
:width: 700
Now, the restriction on voice overlap is reset, but the restriction on the upper parts
being within a perfect octave of each other is removed. fbLine is realized again.
>>> fbRules.forbidVoiceOverlap = True
>>> fbRules.upperPartsMaxSemitoneSeparation = None
>>> fbRealization3 = fbLine.realize(fbRules)
>>> fbRealization3.getNumSolutions()
29629539
>>> fbRealization3.keyboardStyleOutput = False
>>> #_DOCS_SHOW fbRealization3.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol3D.*
:width: 700
'''
s = tinyNotation.TinyNotationStream("BB4 C#4_#6 D4_6 E2 E#4_7,5,#3 F#2_6,4 F#4_5,#3 G2 E4_6 F#2_6,4 E4_#4,2 D2_6 EE4_7,5,#3 AA2.", "3/4")
s.insert(0, key.Key('b'))
return realizer.figuredBassFromStream(s)
def augmentedSixthResolutionExample():
'''
This example was retrieved from page 61 of *The Music Theory Handbook* by Marjorie Merryman.
Italian (8,#6,3), French (#6,4,3), German (#6,5,3), and Swiss (#6,#4,3)
augmented sixth resolutions to
either the major dominant or the major/minor tonic 6,4 are supported.
The first four bars show the
resolutions to the dominant in the order above, while the last bar
shows the German augmented sixth
resolving to the tonic.
>>> from music21.figuredBass import examples
>>> fbLine = examples.augmentedSixthResolutionExample()
>>> fbRealization = fbLine.realize()
>>> #_DOCS_SHOW fbRealization.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_a6.*
:width: 700
'''
from music21 import converter, key
s = converter.parse(
"tinynotation: 4/4 D4 BB-4_8,#6,3 AA2_# D4 BB-4_#6,4,3 " +
"AA2_# D4 BB-4_#6,5,3 AA2_# D4 BB-4_#6,#4,3 AA2_# D4 " +
"BB-4_#6,5,3 AA2_6,4",
makeNotation=False)
s.insert(0, key.Key('d'))
return realizer.figuredBassFromStream(s)
def exampleA():
'''
This example was a homework assignment for 21M.302: Harmony & Counterpoint II
at MIT in the fall of 2010, taught by Charles Shadle of the MIT Music Program.
>>> from music21.figuredBass import examples
>>> fbLine = examples.exampleA()
>>> #_DOCS_SHOW fbLine.generateBassLine().show()
.. image:: images/figuredBass/fbExamples_bassLineA.*
:width: 700
The following is a realization of fbLine in four parts using the default rules set.
The soprano part is limited to stepwise motion, and the alto and tenor parts are
limited to motions within a perfect octave.
>>> from music21.figuredBass import rules
>>> fbRules = rules.Rules()
>>> fbRules.partMovementLimits = [(1, 2), (2, 12), (3, 12)]
>>> fbRealization1 = fbLine.realize(fbRules)
>>> fbRealization1.getNumSolutions()
360
>>> #_DOCS_SHOW fbRealization1.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol1A.*
:width: 700
Now, the restriction on upper parts being within a perfect octave of each other is
removed, and fbLine is realized again.
>>> fbRules.upperPartsMaxSemitoneSeparation = None
>>> fbRealization2 = fbLine.realize(fbRules)
>>> fbRealization2.keyboardStyleOutput = False
>>> fbRealization2.getNumSolutions()
3713168
>>> #_DOCS_SHOW fbRealization2.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol2A.*
:width: 700
'''
from music21 import converter
s = converter.parse(
"tinynotation: 3/2 C2 D2_6 E2_6 F2_6 C#2_b7,5,3 D2 "
"BB2_#6,5,3 C2_6 AA#2_7,5,#3 BB1_6,4 BB2_7,#5,#3 E1.",
makeNotation=False)
return realizer.figuredBassFromStream(s)
def exampleA():
"""
This example was a homework assignment for 21M.302: Harmony & Counterpoint II
at MIT in the fall of 2010, taught by Charles Shadle of the MIT Music Program.
>>> from music21.figuredBass import examples
>>> fbLine = examples.exampleA()
>>> #_DOCS_SHOW fbLine.generateBassLine().show()
.. image:: images/figuredBass/fbExamples_bassLineA.*
:width: 700
The following is a realization of fbLine in four parts using the default rules set.
The soprano part is limited to stepwise motion, and the alto and tenor parts are
limited to motions within a perfect octave.
>>> from music21.figuredBass import rules
>>> fbRules = rules.Rules()
>>> fbRules.partMovementLimits = [(1,2),(2,12),(3,12)]
>>> fbRealization1 = fbLine.realize(fbRules)
>>> fbRealization1.getNumSolutions()
360
>>> #_DOCS_SHOW fbRealization1.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol1A.*
:width: 700
Now, the restriction on upper parts being within a perfect octave of each other is
removed, and fbLine is realized again.
>>> fbRules.upperPartsMaxSemitoneSeparation = None
>>> fbRealization2 = fbLine.realize(fbRules)
>>> fbRealization2.keyboardStyleOutput = False
>>> fbRealization2.getNumSolutions()
3713168
>>> #_DOCS_SHOW fbRealization2.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol2A.*
:width: 700
"""
from music21 import tinyNotation
s = tinyNotation.TinyNotationStream(
"C2 D2_6 E2_6 F2_6 C#2_b7,5,3 D2 BB2_#6,5,3 C2_6 AA#2_7,5,#3 BB1_6,4 BB2_7,#5,#3 E1.", "3/2"
)
return realizer.figuredBassFromStream(s)
def V43ResolutionExample():
'''
The dominant 4,3 can resolve to either the tonic 5,3 or tonic 6,3. The proper resolution
is dependent on the bass note of the tonic, and is determined in context, as shown in the
following figured bass realization.
>>> from music21.figuredBass import examples
>>> fbLine = examples.V43ResolutionExample()
>>> fbRealization = fbLine.realize()
>>> #_DOCS_SHOW fbRealization.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_V43.*
:width: 350
'''
s = tinyNotation.TinyNotationStream("D2 E2_4,3 D2_5,3 E2_4,3 F#1_6,3", "4/4")
s.insert(0, key.Key('D'))
return realizer.figuredBassFromStream(s)
def exampleC():
'''
This example was retrieved from page 114 of *The Music Theory Handbook* by Marjorie Merryman.
>>> from music21.figuredBass import examples
>>> fbLine = examples.exampleC()
>>> #_DOCS_SHOW fbLine.generateBassLine().show()
.. image:: images/figuredBass/fbExamples_bassLineC.*
:width: 700
First, fbLine is realized with the default rules set.
>>> fbRealization1 = fbLine.realize()
>>> fbRealization1.getNumSolutions()
833
>>> #_DOCS_SHOW fbRealization1.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol1C.*
:width: 700
Now, parallel fifths are allowed in realizations. The image below
shows one of them. There is a parallel fifth between the bass and
alto parts going from the half-diminished 6,5 (B,F#) to the dominant
seventh (C#,G#) in the second measure.
>>> from music21.figuredBass import rules
>>> fbRules = rules.Rules()
>>> fbRules.forbidParallelFifths = False
>>> fbRealization2 = fbLine.realize(fbRules)
>>> fbRealization2.getNumSolutions()
2427
>>> #_DOCS_SHOW fbRealization2.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol2C.*
:width: 700
'''
from music21 import converter
from music21 import key
s = converter.parse(
"tinynotation: 4/4 FF#4 GG#4_#6 AA4_6 FF#4 BB4_6,5 C#4_7,5,#3 F#2",
makeNotation=False)
s.insert(0, key.Key('f#'))
return realizer.figuredBassFromStream(s)
def exampleB():
'''
This example was retrieved from page 114 of *The Music Theory Handbook* by Marjorie Merryman.
>>> from music21.figuredBass import examples
>>> fbLine = examples.exampleB()
>>> #_DOCS_SHOW fbLine.generateBassLine().show()
.. image:: images/figuredBass/fbExamples_bassLineB.*
:width: 700
First, fbLine is realized with the default rules set.
>>> fbRealization1 = fbLine.realize()
>>> fbRealization1.getNumSolutions()
422
>>> #_DOCS_SHOW fbRealization1.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol1B.*
:width: 700
Now, a Rules object is created, and the restriction that the chords
need to be complete is lifted. fbLine is realized once again.
>>> from music21.figuredBass import rules
>>> fbRules = rules.Rules()
>>> fbRules.forbidIncompletePossibilities = False
>>> fbRealization2 = fbLine.realize(fbRules)
>>> fbRealization2.getNumSolutions()
188974
>>> #_DOCS_SHOW fbRealization2.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol2B.*
:width: 700
'''
from music21 import converter
from music21 import key
s = converter.parse(
"tinynotation: 4/4 D4 A4_7,5,#3 B-4 F4_6 G4_6 AA4_7,5,#3 D2",
makeNotation=False)
s.insert(0, key.Key('d'))
return realizer.figuredBassFromStream(s)
def V43ResolutionExample():
'''
The dominant 4,3 can resolve to either the tonic 5,3 or tonic 6,3. The proper resolution
is dependent on the bass note of the tonic, and is determined in context, as shown in the
following figured bass realization.
>>> from music21.figuredBass import examples
>>> fbLine = examples.V43ResolutionExample()
>>> fbRealization = fbLine.realize()
>>> #_DOCS_SHOW fbRealization.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_V43.*
:width: 350
'''
from music21 import converter, key
s = converter.parse("tinynotation: 4/4 D2 E2_4,3 D2_5,3 E2_4,3 F#1_6,3", makeNotation=False)
s.insert(0, key.Key('D'))
return realizer.figuredBassFromStream(s)
def exampleC():
"""
This example was retrieved from page 114 of *The Music Theory Handbook* by Marjorie Merryman.
>>> from music21.figuredBass import examples
>>> fbLine = examples.exampleC()
>>> #_DOCS_SHOW fbLine.generateBassLine().show()
.. image:: images/figuredBass/fbExamples_bassLineC.*
:width: 700
First, fbLine is realized with the default rules set.
>>> fbRealization1 = fbLine.realize()
>>> fbRealization1.getNumSolutions()
833
>>> #_DOCS_SHOW fbRealization1.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol1C.*
:width: 700
Now, parallel fifths are allowed in realizations. The image below
shows one of them. There is a parallel fifth between the bass and
alto parts going from the half-diminished 6,5 (B,F#) to the dominant
seventh (C#,G#) in the second measure.
>>> from music21.figuredBass import rules
>>> fbRules = rules.Rules()
>>> fbRules.forbidParallelFifths = False
>>> fbRealization2 = fbLine.realize(fbRules)
>>> fbRealization2.getNumSolutions()
2427
>>> #_DOCS_SHOW fbRealization2.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol2C.*
:width: 700
"""
from music21 import tinyNotation, key
s = tinyNotation.TinyNotationStream("FF#4 GG#4_#6 AA4_6 FF#4 BB4_6,5 C#4_7,5,#3 F#2", "4/4")
s.insert(0, key.Key("f#"))
return realizer.figuredBassFromStream(s)
def exampleB():
"""
This example was retrieved from page 114 of *The Music Theory Handbook* by Marjorie Merryman.
>>> from music21.figuredBass import examples
>>> fbLine = examples.exampleB()
>>> #_DOCS_SHOW fbLine.generateBassLine().show()
.. image:: images/figuredBass/fbExamples_bassLineB.*
:width: 700
First, fbLine is realized with the default rules set.
>>> fbRealization1 = fbLine.realize()
>>> fbRealization1.getNumSolutions()
422
>>> #_DOCS_SHOW fbRealization1.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol1B.*
:width: 700
Now, a Rules object is created, and the restriction that the chords
need to be complete is lifted. fbLine is realized once again.
>>> from music21.figuredBass import rules
>>> fbRules = rules.Rules()
>>> fbRules.forbidIncompletePossibilities = False
>>> fbRealization2 = fbLine.realize(fbRules)
>>> fbRealization2.getNumSolutions()
188974
>>> #_DOCS_SHOW fbRealization2.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol2B.*
:width: 700
"""
from music21 import tinyNotation, key
s = tinyNotation.TinyNotationStream("D4 A4_7,5,#3 B-4 F4_6 G4_6 AA4_7,5,#3 D2", "4/4")
s.insert(0, key.Key("d"))
return realizer.figuredBassFromStream(s)
def twelveBarBlues():
'''
This is an progression in Bb major based on the twelve bar blues. The progression used is:
I | IV | I | I7
IV | IV | I | I7
V7 | IV6 | I | I
>>> from music21.figuredBass import examples
>>> from music21.figuredBass import rules
>>> bluesLine = examples.twelveBarBlues()
>>> #_DOCS_SHOW bluesLine.generateBassLine().show()
.. image:: images/figuredBass/fbExamples_bluesBassLine.*
:width: 700
>>> fbRules = rules.Rules()
>>> fbRules.partMovementLimits = [(1,4),(2,12),(3,12)]
>>> fbRules.forbidVoiceOverlap = False
>>> blRealization = bluesLine.realize(fbRules)
>>> blRealization.getNumSolutions()
2224978
>>> #_DOCS_SHOW blRealization.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_twelveBarBlues.*
:width: 700
'''
from music21 import converter, key
s = converter.parse(
"tinynotation: BB-1 E-1 BB-1 BB-1_7 E-1 E-1 BB-1 BB-1_7 F1_7 G1_6 BB-1 BB-1",
makeNotation=False)
s.insert(0, key.Key('B-'))
return realizer.figuredBassFromStream(s)
def exampleD():
'''
This example was a homework assignment for 21M.302: Harmony & Counterpoint II
at MIT in the fall of 2010, taught by Charles Shadle of the MIT Music Program.
>>> from music21.figuredBass import examples
>>> fbLine = examples.exampleD()
>>> #_DOCS_SHOW fbLine.generateBassLine().show()
.. image:: images/figuredBass/fbExamples_bassLineD.*
:width: 700
The following is a realization of fbLine in four parts using the default rules set.
The soprano part is limited to stepwise motion, and the alto and tenor parts are
limited to motions within a perfect octave.
>>> from music21.figuredBass import rules
>>> fbRules = rules.Rules()
>>> fbRules.partMovementLimits = [(1,2),(2,12),(3,12)]
>>> fbRealization1 = fbLine.realize(fbRules)
>>> fbRealization1.getNumSolutions()
1560
>>> #_DOCS_SHOW fbRealization1.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol1D.*
:width: 700
Now, the restriction on voice overlap is lifted, which is common in keyboard-style
figured bass, and fbLine is realized again. Voice overlap can be seen in the fourth
measure.
>>> fbRules.forbidVoiceOverlap = False
>>> fbRealization2 = fbLine.realize(fbRules)
>>> fbRealization2.getNumSolutions()
109006
>>> #_DOCS_SHOW fbRealization2.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol2D.*
:width: 700
Now, the restriction on voice overlap is reset, but the restriction on the upper parts
being within a perfect octave of each other is removed. fbLine is realized again.
>>> fbRules.forbidVoiceOverlap = True
>>> fbRules.upperPartsMaxSemitoneSeparation = None
>>> fbRealization3 = fbLine.realize(fbRules)
>>> fbRealization3.getNumSolutions()
29629539
>>> fbRealization3.keyboardStyleOutput = False
>>> #_DOCS_SHOW fbRealization3.generateRandomRealization().show()
.. image:: images/figuredBass/fbExamples_sol3D.*
:width: 700
'''
from music21 import converter, key
s = converter.parse(
"tinynotation: 3/4 BB4 C#4_#6 D4_6 E2 E#4_7,5,#3 F#2_6,4 " +
"F#4_5,#3 G2 E4_6 F#2_6,4 E4_#4,2 D2_6 EE4_7,5,#3 AA2.",
makeNotation=False)
s.insert(0, key.Key('b'))
return realizer.figuredBassFromStream(s)
