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method ConcreteScale.deriveByDegree not working for scale.MelodicMinorScale for some degrees #1649

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me-kell opened this issue Sep 23, 2023 · 1 comment
Open

method ConcreteScale.deriveByDegree not working for scale.MelodicMinorScale for some degrees #1649

me-kell opened this issue Sep 23, 2023 · 1 comment

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@me-kell
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me-kell commented Sep 23, 2023

music21 version

9.1.0

Problem summary

The method ConcreteScale.deriveByDegree is not working for scale.MelodicMinorScale for some degrees (e.g. 6, and 7).

Steps to reproduce

>>> scale.MelodicMinorScale('c').deriveByDegree(6, 'c')

...
music21.scale.intervalNetwork.IntervalNetworkException: could not find any edges

All other scales and degrees seem to work as expected.

for s in [
    scale.MelodicMinorScale,
    scale.MinorScale,
    scale.MajorScale,
    scale.HarmonicMinorScale,
    scale.OctatonicScale,
    scale.WholeToneScale,
    scale.ChromaticScale,
]:
    sc = s('c')
    print(sc.name)
    print([p.name for p in sc.pitches])
    for i in range(1, len(sc.pitches)):
        try:
            derived1 = sc.deriveByDegree(i, "c")
            pitches = [p.name for p in derived1.pitches]
        except Exception as e:
            pitches = f"Exception: {e}"
        print(i, pitches)

Expected vs. actual behavior

Actual behaviour: see output on C melodic minor for degrees 6 and 7.

C melodic minor
['C', 'D', 'E-', 'F', 'G', 'A', 'B', 'C']
1 ['C', 'D', 'E-', 'F', 'G', 'A', 'B', 'C']
2 ['B-', 'C', 'D-', 'E-', 'F', 'G', 'A', 'B-']
3 ['A', 'B', 'C', 'D', 'E', 'F#', 'G#', 'A']
4 ['G', 'A', 'B-', 'C', 'D', 'E', 'F#', 'G']
5 ['F', 'G', 'A-', 'B-', 'C', 'D', 'E', 'F']
6 Exception: could not find any edges
7 Exception: could not find any edges
C minor
['C', 'D', 'E-', 'F', 'G', 'A-', 'B-', 'C']
1 ['C', 'D', 'E-', 'F', 'G', 'A-', 'B-', 'C']
2 ['B-', 'C', 'D-', 'E-', 'F', 'G-', 'A-', 'B-']
3 ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'A']
4 ['G', 'A', 'B-', 'C', 'D', 'E-', 'F', 'G']
5 ['F', 'G', 'A-', 'B-', 'C', 'D-', 'E-', 'F']
6 ['E', 'F#', 'G', 'A', 'B', 'C', 'D', 'E']
7 ['D', 'E', 'F', 'G', 'A', 'B-', 'C', 'D']
C major
['C', 'D', 'E', 'F', 'G', 'A', 'B', 'C']
1 ['C', 'D', 'E', 'F', 'G', 'A', 'B', 'C']
2 ['B-', 'C', 'D', 'E-', 'F', 'G', 'A', 'B-']
3 ['A-', 'B-', 'C', 'D-', 'E-', 'F', 'G', 'A-']
4 ['G', 'A', 'B', 'C', 'D', 'E', 'F#', 'G']
5 ['F', 'G', 'A', 'B-', 'C', 'D', 'E', 'F']
6 ['E-', 'F', 'G', 'A-', 'B-', 'C', 'D', 'E-']
7 ['D-', 'E-', 'F', 'G-', 'A-', 'B-', 'C', 'D-']
C harmonic minor
['C', 'D', 'E-', 'F', 'G', 'A-', 'B', 'C']
1 ['C', 'D', 'E-', 'F', 'G', 'A-', 'B', 'C']
2 ['B-', 'C', 'D-', 'E-', 'F', 'G-', 'A', 'B-']
3 ['A', 'B', 'C', 'D', 'E', 'F', 'G#', 'A']
4 ['G', 'A', 'B-', 'C', 'D', 'E-', 'F#', 'G']
5 ['F', 'G', 'A-', 'B-', 'C', 'D-', 'E', 'F']
6 ['E', 'F#', 'G', 'A', 'B', 'C', 'D#', 'E']
7 ['D-', 'E-', 'F-', 'G-', 'A-', 'B--', 'C', 'D-']
C Octatonic
['C', 'D', 'E-', 'F', 'G-', 'A-', 'A', 'B', 'C']
1 ['C', 'D', 'E-', 'F', 'G-', 'A-', 'A', 'B', 'C']
2 ['B-', 'C', 'D-', 'E-', 'F-', 'G-', 'G', 'A', 'B-']
3 ['A', 'B', 'C', 'D', 'E-', 'F', 'G-', 'A-', 'A']
4 ['G', 'A', 'B-', 'C', 'D-', 'E-', 'F-', 'G-', 'G']
5 ['G-', 'A-', 'A', 'B', 'C', 'D', 'E-', 'F', 'G-']
6 ['F-', 'G-', 'G', 'A', 'B-', 'C', 'D-', 'E-', 'F-']
7 ['E-', 'F', 'G-', 'A-', 'A', 'B', 'C', 'D', 'E-']
8 ['D-', 'E-', 'F-', 'G-', 'G', 'A', 'B-', 'C', 'D-']
C Whole tone
['C', 'D', 'E', 'F#', 'G#', 'A#', 'B#']
1 ['C', 'D', 'E', 'F#', 'G#', 'A#', 'B#']
2 ['B-', 'C', 'D', 'E', 'F#', 'G#', 'A#']
3 ['A-', 'B-', 'C', 'D', 'E', 'F#', 'G#']
4 ['G-', 'A-', 'B-', 'C', 'D', 'E', 'F#']
5 ['F-', 'G-', 'A-', 'B-', 'C', 'D', 'E']
6 ['D', 'E', 'F#', 'G#', 'A#', 'B#', 'D']
C Chromatic
['C', 'C#', 'D', 'E-', 'E', 'F', 'F#', 'G', 'A-', 'A', 'B-', 'B', 'C']
1 ['C', 'C#', 'D', 'E-', 'E', 'F', 'F#', 'G', 'A-', 'A', 'B-', 'B', 'C']
2 ['B', 'C', 'C#', 'D', 'E-', 'E', 'F', 'F#', 'G', 'A-', 'A', 'B-', 'B']
3 ['B-', 'B', 'C', 'C#', 'D', 'E-', 'E', 'F', 'F#', 'G', 'A-', 'A', 'B-']
4 ['A', 'B-', 'B', 'C', 'C#', 'D', 'E-', 'E', 'F', 'F#', 'G', 'A-', 'A']
5 ['G#', 'A', 'B-', 'B', 'C', 'C#', 'D', 'E-', 'E', 'F', 'F#', 'G', 'A-']
6 ['G', 'A-', 'A', 'B-', 'B', 'C', 'C#', 'D', 'E-', 'E', 'F', 'F#', 'G']
7 ['F#', 'G', 'A-', 'A', 'B-', 'B', 'C', 'C#', 'D', 'E-', 'E', 'F', 'F#']
8 ['F', 'F#', 'G', 'A-', 'A', 'B-', 'B', 'C', 'C#', 'D', 'E-', 'E', 'F']
9 ['E', 'F', 'F#', 'G', 'A-', 'A', 'B-', 'B', 'C', 'C#', 'D', 'E-', 'E']
10 ['E-', 'E', 'F', 'F#', 'G', 'A-', 'A', 'B-', 'B', 'C', 'C#', 'D', 'E-']
11 ['D', 'E-', 'E', 'F', 'F#', 'G', 'A-', 'A', 'B-', 'B', 'C', 'C#', 'D']
12 ['C#', 'D', 'E-', 'E', 'F', 'F#', 'G', 'A-', 'A', 'B-', 'B', 'C', 'C#']
@me-kell
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me-kell commented Sep 23, 2023 •
edited
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I'm not sure but the edges of the intervaleNetwork of the MelodicMinorScale have a different pattern/structure than in other scales. Specially #6 and #7:

for s in [
    scale.MelodicMinorScale,
    scale.MinorScale,
    scale.MajorScale,
    scale.HarmonicMinorScale,
    scale.OctatonicScale,
    scale.WholeToneScale,
    scale.ChromaticScale,
]:
    sc = s('c')
    print(sc.name)
    pprint.pprint(sc._abstract._net.edges)
C melodic minor
OrderedDict([(0, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(Terminus.LOW, 0), (0, Terminus.LOW)]>),
             (1, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(0, 1), (1, 0)]>),
             (2, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(1, 2), (2, 1)]>),
             (3, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(2, 3), (3, 2)]>),
             (4, <music21.scale.intervalNetwork.Edge Direction.ASCENDING M2 [(3, 4)]>),
             (5, <music21.scale.intervalNetwork.Edge Direction.ASCENDING M2 [(4, 6)]>),
             (6, <music21.scale.intervalNetwork.Edge Direction.ASCENDING m2 [(6, Terminus.HIGH)]>),
             (7, <music21.scale.intervalNetwork.Edge Direction.DESCENDING M2 [(Terminus.HIGH, 7)]>),
             (8, <music21.scale.intervalNetwork.Edge Direction.DESCENDING M2 [(7, 5)]>),
             (9, <music21.scale.intervalNetwork.Edge Direction.DESCENDING m2 [(5, 3)]>)])
C minor
OrderedDict([(0, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(Terminus.LOW, 0), (0, Terminus.LOW)]>),
             (1, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(0, 1), (1, 0)]>),
             (2, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(1, 2), (2, 1)]>),
             (3, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(2, 3), (3, 2)]>),
             (4, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(3, 4), (4, 3)]>),
             (5, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(4, 5), (5, 4)]>),
             (6, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(5, Terminus.HIGH), (Terminus.HIGH, 5)]>)])
C major
OrderedDict([(0, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(Terminus.LOW, 0), (0, Terminus.LOW)]>),
             (1, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(0, 1), (1, 0)]>),
             (2, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(1, 2), (2, 1)]>),
             (3, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(2, 3), (3, 2)]>),
             (4, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(3, 4), (4, 3)]>),
             (5, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(4, 5), (5, 4)]>),
             (6, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(5, Terminus.HIGH), (Terminus.HIGH, 5)]>)])
C harmonic minor
OrderedDict([(0, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(Terminus.LOW, 0), (0, Terminus.LOW)]>),
             (1, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(0, 1), (1, 0)]>),
             (2, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(1, 2), (2, 1)]>),
             (3, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(2, 3), (3, 2)]>),
             (4, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(3, 4), (4, 3)]>),
             (5, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(4, 5), (5, 4)]>),
             (6, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(5, Terminus.HIGH), (Terminus.HIGH, 5)]>)])
C Octatonic
OrderedDict([(0, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(Terminus.LOW, 0), (0, Terminus.LOW)]>),
             (1, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(0, 1), (1, 0)]>),
             (2, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(1, 2), (2, 1)]>),
             (3, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(2, 3), (3, 2)]>),
             (4, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(3, 4), (4, 3)]>),
             (5, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(4, 5), (5, 4)]>),
             (6, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(5, 6), (6, 5)]>),
             (7, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(6, Terminus.HIGH), (Terminus.HIGH, 6)]>)])
C Whole tone
OrderedDict([(0, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(Terminus.LOW, 0), (0, Terminus.LOW)]>),
             (1, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(0, 1), (1, 0)]>),
             (2, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(1, 2), (2, 1)]>),
             (3, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(2, 3), (3, 2)]>),
             (4, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(3, 4), (4, 3)]>),
             (5, <music21.scale.intervalNetwork.Edge Direction.BI M2 [(4, Terminus.HIGH), (Terminus.HIGH, 4)]>)])
C Chromatic
OrderedDict([(0, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(Terminus.LOW, 0), (0, Terminus.LOW)]>),
             (1, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(0, 1), (1, 0)]>),
             (2, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(1, 2), (2, 1)]>),
             (3, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(2, 3), (3, 2)]>),
             (4, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(3, 4), (4, 3)]>),
             (5, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(4, 5), (5, 4)]>),
             (6, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(5, 6), (6, 5)]>),
             (7, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(6, 7), (7, 6)]>),
             (8, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(7, 8), (8, 7)]>),
             (9, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(8, 9), (9, 8)]>),
             (10, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(9, 10), (10, 9)]>),
             (11, <music21.scale.intervalNetwork.Edge Direction.BI m2 [(10, Terminus.HIGH), (Terminus.HIGH, 10)]>)])

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