Generation

TECHNICAL_GUIDE.md

@@ -122,7 +122,9 @@ Measure durations, event onsets/durations, harmony offsets, span times, and pitc
 
 ### Shared Part Generation
 
-`parts.py` owns shared source validation, melody-copying, measure construction, rests, and solo slashes. `rhythm.py` loads snippets; `accompaniment.py` plans phrase cycles and realizes independent bass/upper voices or electric stabs. `melody.py` identifies long tied melody runs and splits them at harmony changes before guitar placement. `arrange/generate.py` supplies the existing seven-section song form; `practice/generate.py` supplies a single source pass. `pitch.py` resolves source instrument transposition and the shared written-octave convention. There is no generic twelve-key transposer or separate practice fretboard solver.
+`parts.py` owns shared source validation, melody-copying, measure construction, rests, and solo slashes. `rhythm.py` loads snippets; `accompaniment.py` plans phrase cycles and realizes independent bass/upper voices or electric stabs. After guitar placement and continuation linking, `acoustic.py` combines generated bass/upper lanes into one notated voice. `melody.py` identifies long tied melody runs and splits them at harmony changes before guitar placement. `arrange/generate.py` supplies the existing seven-section song form; `practice/generate.py` supplies a single source pass. `pitch.py` resolves source instrument transposition and the shared written-octave convention. There is no generic twelve-key transposer or separate practice fretboard solver.
+
+Acoustic consolidation preserves the exact sounding-note timeline and TAB assignments. It combines simultaneous tones, splits sustains at intervening attacks/releases, and ties only fragments of the same sounding note or existing tie chain. Repeated pitches remain fresh attacks. Rests represent complete silence, with one measure rest for a silent full bar. Independent stem directions and old beam groups are removed; standard single-voice engraving supplies shared stems and automatic beams. Binary durations that require multiple written values become ordinary tied notes rather than artificial tuplets. Exact nonbinary timing retains the model's rational time modifications. This pass leaves authored voices and solo slashes unchanged and runs entirely at build time.
 
 Practice acoustic accompaniment is derived from structured harmony roots, kinds, degrees, inversions, and slash basses using the same generation rules as songs. A missing harmony or N.C. produces rests, not guessed chords. Electric retains the melody's register and spelling while adding playable chords to long notes. Vocal retains authored notes and receives scat lyrics. Song vocal lyrics are unchanged. Practice optional-turnaround harmonies are played once, without creating extra sections.
 
@@ -134,13 +136,13 @@ All three parts, for both songs and practice, use octave-transposing notation: w
 
 `pitch.py` resolves explicit MusicXML instrument transposition once before part generation. Explicit zero transposition is also authoritative. Octave-clef exports already encode sounding pitch in their note values, so they do not receive another implicit octave subtraction. Generated parts carry an explicit `transpose.octave_change: -1`; guitar placement and audio read that shared state. Internal concert-pitch normalization and written-pitch conversion cancel for ordinary source notation except for the intentional song electric melody octave increase. There is no automatic octave fitting, vocal-specific range shift, or key transposition.
 
-`guitar.py` searches standard tuning E2 A2 D3 G3 B3 E4, frets 0-20 inclusive, with at most four frets between fretted positions; open strings do not count toward that span. Exact melody tones are never dropped or replaced. Simultaneous tones occupy distinct strings, and sustained/tied tones retain their assignments. Acoustic grips use one bass on string 5 or 6 and two or three consecutive strings within 2-4, with zero or one unused string between bass and upper voices. Both rhythmic voices must fit one complete grip, even when only one attacks. Bass alternates root and chord fifth, restarting at harmony/section changes; explicit basses/inversions remain fixed. A fifth-bass choice falls back to the root if it cannot preserve chord identity and the held strings.
+`guitar.py` searches standard tuning E2 A2 D3 G3 B3 E4, frets 0-20 inclusive, with at most four frets between the lowest and highest positions, including fret 0. Open strings participate in span validation and proximity scoring: 0/2/3 and 0/4 are valid, while 0/5 and 0/11/12 are not. Exact melody tones are never dropped or replaced. Simultaneous tones occupy distinct strings, and sustained/tied tones retain their assignments. Acoustic grips use one bass on string 5 or 6 and two or three consecutive strings within 2-4, with zero or one unused string between bass and upper voices. Both rhythmic voices must fit one complete grip, even when only one attacks. Bass alternates root and chord fifth, restarting at harmony/section changes; explicit basses/inversions remain fixed. A fifth-bass choice falls back to the root if it cannot preserve chord identity and the held strings.
 
 Electric chord blocks use strings 1-3 or 1-4, including string 1. Rootless voicings and octave doublings are allowed; the third or suspension, sixth/seventh, alterations, and named extensions remain required. An unaltered fifth in extended chords and unaltered intermediate ninth/eleventh extensions may be omitted. Melody notes can lie below added chord tones, including non-chord melody pitches that must remain unchanged.
 
 `melody.py` treats the full tied duration as one note when testing whether it exceeds one quarter-note beat. Qualifying notes receive a chord at their initial attack and at each subsequent changed harmony, even if a resulting fragment is less than one beat. Changed harmonies break ties and reattack the melody; repeated identical harmonies do not. N.C. releases the added voices while preserving the melody's sustain. Added tones through unchanged harmony retain their own ties. The quarter-note cap on electric stabs does not apply to these melody chords. If no valid chord fits, the exact melody remains with a diagnostic; it is not octave-wrapped or omitted.
 
-Placement minimizes total movement of fret/string position centers, then fretted span and omitted optional degrees, with deterministic ties. Independent attacks use an exact small-grid distance transform; when notes sustain across attacks the search retains actual occupied strings. There is no finger assignment, barre logic, or predefined chord-shape dictionary. These are proximity and fretboard-feasibility constraints, not a guarantee of comfortable fingering. Nonstandard tuning, capos, microtonal frets, and unplayable passages fail with source/part/event context; there is no slash fallback for a failed chord. Existing assets remain untouched after failure.
+Placement minimizes total movement of fret/string position centers, then fret span and omitted optional degrees, with deterministic ties. All three calculations include open strings. Independent attacks use an exact small-grid distance transform; when notes sustain across attacks the search retains actual occupied strings. There is no finger assignment, barre logic, or predefined chord-shape dictionary. These are proximity and fretboard-feasibility constraints, not a guarantee of comfortable fingering. Nonstandard tuning, capos, microtonal frets, and unplayable passages fail with source/part/event context; there is no slash fallback for a failed chord. Existing assets remain untouched after failure.
 
 ### Practice Scat