khodowany
118 lines
5.7 KiB
Python
118 lines
5.7 KiB
Python
"""Accepted, paired pitch/rhythm examples; production uses contextual profiles."""
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from __future__ import annotations
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import dataclasses
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import fractions
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import hashlib
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import json
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import pathlib
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import generator.harmony
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import generator.model
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import generator.solo.types as types
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F = fractions.Fraction
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@dataclasses.dataclass(frozen=True)
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class ReferencePhrase:
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id: str
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version: str
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notes: tuple[types.Note, ...]
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decorated: tuple[types.Note, ...]
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duration: F
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tonic: int
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harmony: tuple[tuple[F, str], ...]
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features: tuple[tuple[str, F, F], ...]
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runs: tuple[tuple[F, F], ...]
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acceptance: str
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development: tuple[tuple[str, F, F, tuple[int, ...]], ...] = ()
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def windows(self):
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# Windows retain their parent and context; they are not separate approvals.
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result = []
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for length in (F(8), F(16)):
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for start in range(0, int(self.duration), int(length)):
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end = min(self.duration, start + length)
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selected = tuple(dataclasses.replace(n, start=n.start - start, end=n.end - start) for n in self.notes if start <= n.start and n.end <= end)
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if len(selected) >= 2:
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chords = tuple(chord for time, chord in self.harmony if start <= time < end)
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result.append(types.Motif(f'{self.id}:{start}:{end}', selected, end - start, chords, 'accepted reference profile'))
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return tuple(result)
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def read(path):
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raw = path.read_bytes()
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data = json.loads(raw)
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if data['pitch_convention'] != 'sounding' or not data.get('acceptance'):
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raise ValueError(f'{path}: reference requires sounding pitches and explicit acceptance provenance')
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def notes(variant):
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result, cursor = [], F()
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for i, event in enumerate(data['variants'][variant]['events']):
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start, duration = F(event['onset_beats']), F(event['duration_beats'])
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if start != cursor or duration <= 0:
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raise ValueError(f'{path}: reference events must fill exact sequential time')
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cursor = start + duration
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if event['pitch'] is None:
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continue
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name = event['pitch']
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pitch = types.Pitch(name[0].lower(), F(1 if '#' in name else -1 if 'b' in name else 0), int(name[-1]))
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if pitch.number() != event['midi_pitch']:
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raise ValueError(f'{path}: inconsistent sounding pitch {name}')
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result.append(types.Note(start, cursor, pitch, (data['id'],), event_id=f'{variant}_{i}'))
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return tuple(result), cursor
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plain, duration = notes('lead_theme')
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decorated, other_duration = notes('lead_with_runs')
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if duration != other_duration or len(plain) != data['variants']['lead_theme']['attacks'] or len(decorated) != data['variants']['lead_with_runs']['attacks']:
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raise ValueError(f'{path}: inconsistent reference variants')
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tonic = generator.model.parse_pitch_name(data['tonic'])
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number = int(generator.model.NATURAL[tonic['letter']] + generator.model.alteration(tonic['alter']))
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harmony = tuple((F(4 * (h['bar'] - 1)), h['chord']) for h in data['harmony'])
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for _, chord in harmony:
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generator.harmony.parse_symbol(chord)
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return ReferencePhrase(data['id'], hashlib.sha256(raw).hexdigest(), plain, decorated, duration, number, harmony,
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tuple((f['id'], F(f['start']), F(f['end'])) for f in data['features']), tuple((F(w['start']), F(w['end'])) for w in data['run_windows']), data['acceptance'],
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tuple((d['role'], F(d['start']), F(d['end']), tuple(d.get('degrees', ()))) for d in data.get('development', ())))
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def load_library(root: pathlib.Path):
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return tuple(read(path) for path in sorted(root.glob('*.json')))
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def identifying_features(notes, source):
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"""Select a characteristic leap followed by return, wherever it occurs."""
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notes = tuple(notes)
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candidates = []
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for i in range(len(notes) - 2):
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a, b, c = notes[i:i + 3]
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leap, reply = b.pitch.number() - a.pitch.number(), c.pitch.number() - b.pitch.number()
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if 3 <= abs(leap) <= 9 and leap * reply < 0 and c.start - a.start <= 4:
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group = notes[i:min(len(notes), i + 4)]
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rhythm = tuple((n.start - a.start, n.end - n.start) for n in group)
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intervals = tuple(y.pitch.number() - x.pitch.number() for x, y in zip(group, group[1:]))
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candidates.append(types.IdentifyingFeature(a.event_id + '_identity', tuple(n.event_id for n in group), rhythm, intervals, source))
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return tuple(candidates[:1])
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def feature_error(feature, notes):
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by_id = {n.event_id: n for n in notes}
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actual = [by_id.get(identity) for identity in feature.events]
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if not all(actual):
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return 1.0
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first = actual[0].start
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rhythm = tuple((n.start - first, n.end - n.start) for n in actual)
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movement = tuple(b.pitch.number() - a.pitch.number() for a, b in zip(actual, actual[1:]))
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timing = sum(a != b for a, b in zip(rhythm, feature.rhythm)) / max(1, len(rhythm))
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contour = sum(((a > 0) - (a < 0)) != ((b > 0) - (b < 0)) or abs(a - b) > 2 for a, b in zip(movement, feature.intervals)) / max(1, len(movement))
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return (timing + contour) / 2
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def relationship(notes, reference):
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"""One joint relationship cost: timed movement, not absolute-pitch copying."""
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notes = tuple(notes)
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if len(notes) < 2 or len(reference.notes) < 2:
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return 0.0 if len(notes) == len(reference.notes) == 1 else 1.0
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actual = tuple(b.pitch.number() - a.pitch.number() for a, b in zip(notes, notes[1:]))
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expected = reference.contour()
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count = min(len(actual), len(expected))
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contour = sum(0.75 * (((a > 0) - (a < 0)) != ((b > 0) - (b < 0))) + 0.25 * min(1, max(0, abs(a - b) - 2) / 7) for a, b in zip(actual, expected)) / max(1, count)
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start, ref_start = notes[0].start, reference.notes[0].start
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rhythm = sum(min(1, float(abs((n.start - start) - (r.start - ref_start))) / 2) for n, r in zip(notes, reference.notes)) / min(len(notes), len(reference.notes))
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evidence = max(0, min(3, len(reference.notes)) - len(notes)) / 3
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return max(evidence, (contour + rhythm) / 2)
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