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small improvements: simplifyingMultiplEnharmonics #1983

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Merged
mscuthbert merged 1 commit into from
Jul 20, 2026
+15 −4
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small improvements: simplifyingMultiplEnharmonics #1983

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2 changes: 1 addition & 1 deletion music21/chord/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -4375,7 +4375,7 @@ def simplifyEnharmonics(
for i in range(len(pitches)):
returnObj._notes[i].pitch = pitches[i]

if inPlace is False:
if not inPlace:
return returnObj

@overload
Expand Down
17 changes: 14 additions & 3 deletions music21/pitch.py
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Original file line number Diff line number Diff line change
Expand Up @@ -539,6 +539,7 @@ def _convertHarmonicToCents(value: int|float) -> int:


def _dissonanceScore(pitches: list[Pitch],
*,
smallPythagoreanRatio: bool = True,
accidentalPenalty: bool = True,
triadAward: bool = True) -> float:
Expand All @@ -549,7 +550,10 @@ def _dissonanceScore(pitches: list[Pitch],
Pythagorean ratios of its constituent intervals are small (`smallPythagoreanRatio`),
(2) it shows few double- or triple-accidentals (`accidentalPenalty`), and (3) it shows
thirds that can form some triad (`triadAward`).

* Changed in v11: all options except pitches are keyword only.
'''
# TODO: test other options.
score_accidentals = 0.0
score_ratio = 0.0
score_triad = 0.0
Expand Down Expand Up @@ -579,6 +583,10 @@ def _dissonanceScore(pitches: list[Pitch],
for this_interval in intervals:
# does not accept weird intervals, e.g. with semitones
ratio = interval.intervalToPythagoreanRatio(this_interval)
# The constant 0.075853.... is 1 / ln(3**12), where 3**12 is 531441, the numerator
# of 531441/524288 -- the Pythagorean comma: it normalizes the penalty so a
# diminished second (the Pythagorean comma; slightly more than a unison),
# scores exactly 1.0, and all other penalties are based on that.
penalty = math.log(ratio.denominator) * 0.07585326888
score_ratio += penalty

Expand Down Expand Up @@ -626,6 +634,7 @@ def _greedyEnharmonicsSearch(

def simplifyMultipleEnharmonics(
pitches: t.Iterable[Pitch|str|int|float],
*,
criterion: t.Callable[[list[Pitch]], float] = _dissonanceScore,
keyContext: key.KeySignature|None = None
) -> list[Pitch]:
Expand Down Expand Up @@ -675,13 +684,15 @@ def simplifyMultipleEnharmonics(
... keyContext=key.Key('C'))
[<music21.pitch.Pitch C3>, <music21.pitch.Pitch E3>, <music21.pitch.Pitch G3>]

* Changed in v7.3: fixed a bug with compound intervals (such as formed against
the tonic of a KeySignature defaulting to octave 4):
Former bug: simplifying enharmonics in a key context will not remove octaves.

>>> pitch.simplifyMultipleEnharmonics([pitch.Pitch('B5')], keyContext=key.Key('D'))
[<music21.pitch.Pitch B5>]
'''

* Changed in v7.3: fixed a bug with compound intervals (such as those formed against
the tonic of a KeySignature defaulting to octave 4).
* Changed in v11: crtierion and keyContext are keyword only.
'''
oldPitches = [p if isinstance(p, Pitch) else Pitch(p) for p in pitches]

if keyContext:
Expand Down
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