khodowany
124 lines
6.3 KiB
Python
124 lines
6.3 KiB
Python
"""Source-only sparse accompaniment, frozen once at each form position."""
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from __future__ import annotations
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import copy
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import functools
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import json
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from fractions import Fraction as F
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from generator import accompaniment, fretboard, guitar, harmony, model, parts, score, vocabulary
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from generator.solo.policy import stable_rank
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def semantic_key(chord):
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return json.dumps({k: chord[k] for k in ('root', 'kind', 'degrees', 'bass', 'inversion') if k in chord}, sort_keys=True)
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@functools.lru_cache(maxsize=2048)
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def voicings(key, bass):
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chord = json.loads(key)
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degrees = harmony.degrees(chord)
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root = int(model.NATURAL[chord['root']['letter']] + model.alteration(chord['root']['alter']))
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classes = {d: (root + harmony.degree_semitones(d, a)) % 12 for d, a in degrees.items()}
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required = {p for d, p in classes.items() if d in (2, 3, 4, 6, 7) or d == 5 and degrees[d] or d > 7}
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full = fretboard.chord_requirements(chord)
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required.update(full.basses)
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if bass and 1 in classes:
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required.add(classes[1])
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if len(required) < 2:
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required.update(classes[d] for d in (1, 5) if d in classes)
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allowed = set(full.allowed)
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requirements = fretboard.ChordRequirements(tuple(sorted(required)), tuple(sorted(allowed)), tuple(sorted(allowed)), full.basses)
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options = guitar.chord_positions(requirements, prune=False)
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size = max(2, len(required))
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options = [v for v in options if len(v) == size and fretboard.playable_attack((p, F(1)) for p in v)]
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if not options:
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raise ValueError(harmony.symbol(chord) + ': no legal sparse voicing preserving essential written degrees')
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# Retain distinct hand regions and inversions, independent of enumeration.
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best = {}
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for v in options:
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family = (min(p.fret for p in v), min(p.midi for p in v) % 12)
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rank = (guitar.compactness(v), stable_rank('comp-voicing', v))
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if family not in best or rank < best[family][0]:
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best[family] = rank, v
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return tuple(v for _, v in sorted(best.values()))
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class Canonical:
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def __init__(self, document, part, seed):
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self.part, self.seed = part, seed
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self.policy = vocabulary.role(part + '_accompaniment')
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self.cache, self.previous, self.report = {}, (), []
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measures = score.source_staff(document)['measures']
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self.first_index = score.body_start_measure_index(measures)
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self.last_index = len(measures)-1
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carried = accompaniment.carried_chords(measures)
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for index in range(score.body_start_measure_index(measures), len(measures)):
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source = copy.deepcopy(measures[index])
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for h in source['harmonies']:
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h.pop('chord_optional', None)
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self(source, carried[index], index)
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def __call__(self, source, prior, index):
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key = (index, tuple((model.fraction(h['onset']), semantic_key(h)) for h in source['harmonies']), semantic_key(prior) if prior else '', source['duration'].__repr__())
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if key in self.cache:
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return copy.deepcopy(self.cache[key])
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length = model.fraction(source['duration'])
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boundaries = sorted({F(), length, *(model.fraction(h['onset']) for h in source['harmonies'])})
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attacks = []
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source_attacks = {model.fraction(n['onset']) for n in score.measure_notes(source) if n['pitches'] and not all('tie_from' in p for p in n['pitches'])}
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for start, end in zip(boundaries, boundaries[1:]):
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chord = accompaniment.active_chord(source, start, prior)
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if not chord:
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continue
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duration = end - start
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# Essential bass is a source-derived form responsibility, independent
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# of which other guitar happens to be playing or what it generated.
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bass = self.policy.get('bass') == 'primary' or bool(chord.get('bass')) or index in (self.first_index,self.last_index) or start > 0
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options = voicings(semantic_key(chord), bass)
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center = self.policy.get('center', 55)
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selected = min(options, key=lambda v: (
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.08 * abs(sum(p.midi for p in v) / len(v) - center)
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+ (.15 * guitar.movement(self.previous, v) if self.previous else 0)
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+ .1 * guitar.compactness(v), stable_rank(self.seed, (index, start, v))))
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self.previous = selected
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patterns = []
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for figure in vocabulary.data('rhythms')['comping']:
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events = tuple((start+F(a), min(end, start+F(a)+F(d))) for a, d in figure['attacks'] if F(a) < duration)
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# Space is available on held harmony, never an accidental empty winner.
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if not events and (not prior or not accompaniment.same_chord(chord, prior) or start):
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continue
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conflicts = sum(a in source_attacks for a, _ in events)
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target = 1 if duration <= 3 else 1.5
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cost = .2*abs(len(events)-target) + .08*conflicts
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if figure['id'] == 'sustain' and duration < 3:
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cost += .2
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patterns.append((cost, stable_rank(self.seed, (index, start, figure['id'])), events, figure['id']))
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# Source-specific variation within a broad acceptability band, not a loop.
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low = min(p[0] for p in patterns)
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_, _, events, label = min((p for p in patterns if p[0] <= low+.25), key=lambda p:p[1])
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for a, b in events:
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attacks.append((a, b, selected, chord))
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self.report.append({'source_index': index, 'onset': str(start), 'chord': harmony.symbol(chord), 'figure': label, 'tones': len(selected), 'bass': bass,
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'fuller_voicing_reason': 'explicit written degrees/bass' if len(selected)>3 else ''})
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notes, cursor = [], F()
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def emit(a, b, positions=(), chord=None):
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nonlocal cursor
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previous = None
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for duration, written in accompaniment.written_durations(b-a):
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pitches = fretboard.chord_pitches(chord, positions) if positions else []
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n = model.make_event(f'comp_{self.part}_{index}_{len(notes)}', a, duration, 'note' if pitches else 'rest', pitches, written)
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if previous:
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for old, new in zip(previous['pitches'], n['pitches']):
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old['tie_to'], new['tie_from'] = new['id'], old['id']
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notes.append(n); previous = n; a += duration
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cursor = b
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for start, end, positions, chord in attacks:
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if cursor < start: emit(cursor, start)
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emit(start, end, positions, chord)
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if cursor < length: emit(cursor, length)
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result = parts.build_measure(source, 'canonical', 'rest', self.part, prior)
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result['voices'] = [{'id': 'voice_arranged', 'notes': notes}]
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for note in notes: note['voice'] = 'voice_arranged'
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self.cache[key] = copy.deepcopy(result)
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return result
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