def _best_sane_chord(preceding, current, following,
recent_notes, chord_index, limiting, net):
r"""
Given a current theoretical chord, find the best plausible form for it.
* `preceding` is a chronological list of preceding chords in physical form.
* `current` is the theoretical chord to be instantiated.
* `following` is a chronological list of following chords.
* `recent_notes` is a mapping from theoretical notes to physical notes;
it indicates what the most recent instance of a particular note was.
* `chord_index` is the chord number of `current`, e.g. 0 if `current` is
the first chord.
* `limiting` is the first "limiting" note part of a chord with an index
strictly greater than `chord_index`.
* `net` is the trained neural net that makes the final decision.
"""
min_error = None
best_config = None
for sane in sane_chords(current):
# TODO move "transformation" to sane_chords where it belongs
transformed_sane = {}
for sane_entry in sane:
string_index = STANDARD_STRINGS.index(sane_entry[1])
transformed_sane[string_index] = sane_entry[0]
LOG.debug('Transformed: {transformed_sane}'.format(**locals()))
error = _sane_chord_error(preceding, transformed_sane, following,
recent_notes, chord_index, limiting, net)
if min_error is None or error < min_error:
min_error = error
best_config = transformed_sane
for elem in best_config:
if elem > 24:
LOG.warning('Outside of fret range!')
return best_config
def _fret_string_combos(note):
r"""
Given a (theoretical) `note`, return all supported fret/string combos,
along with flags indicating whether the returned values are usable.
This assumes that a note can occur in no more than six locations.
To ease testing, entries go from low strings to high strings.
>>> _fret_string_combos(('E', 3))
(12, 5, 1, 7, 4, 1, 2, 3, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0)
"""
result_builder = []
for location in frets(note):
result_builder.append(location[0])
result_builder.append(STANDARD_STRINGS.index(location[1]))
result_builder.append(1)
missing_values = 18 - len(result_builder)
result_builder.extend([0] * missing_values)
return tuple(result_builder)
def annotate(midi_path, net):
r"""
Given a path to a generated midi,
yield the best configuration for each chord.
"""
preceding = []
recent_notes = {}
for (current, following, current_index, limiting) in midi_contexts(midi_path):
# sane_chords actually uses note lists instead of canonical chords
# this is okay for single-note melodies, though
# TODO adjust called code so that this whole hack is not necessary
LOG.debug('Following: {f}'.format(f=following))
following_notelists = []
for theor_following in following:
theor_notelist = []
for key in theor_following.keys():
theor_notelist.extend([key] * theor_following[key])
following_notelists.append(theor_notelist)
LOG.debug('Following notelists: {f}'.format(f=following_notelists))
phys_following = [next(sane_chords(successor)) for successor in following_notelists]
LOG.debug('Phys following: {p}'.format(p=phys_following))
phys_transformed = []
for frozen in phys_following:
el = next(iter(frozen)) # only one, anyway
phys_transformed.append({STANDARD_STRINGS.index(el[1]): el[0]})
LOG.debug('Phys transformed: {p}'.format(p=phys_transformed))
best_config = _best_sane_chord(preceding, current, phys_transformed,
recent_notes, current_index,
limiting, net)
yield best_config
if len(preceding) >= CHORDS_BEFORE_CURRENT:
del(preceding[0])
preceding.append(best_config)
for string_num in best_config:
fret = best_config[string_num]
recent_notes[fret2note(fret, string_num)] = (string_num, fret)
def _sample_data(preceding, current_chord, following, recent_notes,
current_chord_index, limiting_note):
r"""
Transform a given chord context into an input-output pair for an ANN.
Given a dataset and a chord context, this function yields pairs of
input and output values *for each note in the current chord*.
`recent_notes` is a dict-like object which, for each (theoretical)
note, specifies the most recent fret and string values (bundled in
an indexed sequence).
`limiting_note`, if any value, is a tuple whose elements are:
#. the next (theoretical) limiting note,
i.e. the first note that comes after `current_chord` and
which imposes strict constraints on where it can be played
#. the chord index of that note
Chords belonging to the chord context are specified in their physical
form. This includes the current chord and successor chords.
"""
LOG.debug('Current chord: {current}'.format(current=current_chord))
highest_note_chord = _highest_note_chord(current_chord)
lowest_note_chord = _lowest_note_chord(current_chord)
avg_frets = _avg_frets(preceding)
preceding_notes = _pad_physical_notes(_adjacent_notes(preceding, 4), 4)
following_notes = _pad_physical_notes(_adjacent_notes(following, 6, fwd=True), 6)
LOG.debug('Following notes: {f}'.format(f=following_notes))
following_notes = [fret2note(phys[1], phys[0]) for phys in list(following_notes)]
if limiting_note:
to_limiting_note = limiting_note[1] - current_chord_index
minimal_fret_limiting_note = None
for fret in frets(limiting_note[0]):
if minimal_fret_limiting_note is None or fret[0] < minimal_fret_limiting_note:
minimal_fret_limiting_note = fret[0]
minimal_string_limiting_note = STANDARD_STRINGS.index(fret[1])
limiting_note_flag = 1
else:
to_limiting_note = 1000 # just use something so big it is irrelevant
minimal_fret_limiting_note = 0
minimal_string_limiting_note = 0
limiting_note_flag = 0
if preceding:
num_notes_prev_chord = len(preceding[-1])
else:
num_notes_prev_chord = 0
if len(preceding) > 1:
num_notes_prev_chord_2 = len(preceding[-2])
else:
num_notes_prev_chord_2 = 0
if following:
num_notes_next_chord = len(following[0])
else:
num_notes_next_chord = 0
if len(following) > 1:
num_notes_next_chord_2 = len(following[1])
else:
num_notes_next_chord_2 = 0
for string_num in sorted(current_chord.keys()):
note = fret2note(current_chord[string_num], string_num)
recent_note = recent_notes.get(note, (0, 0))
fret_string_combos = _fret_string_combos(note)
bits = [0] * SUPPORTED_FRETS
bits[current_chord[string_num]] = 1 # fret alone is fine
inputs = (# 1: notes in current chord
len(current_chord.keys()),
# 2-3: current note octave and value
int(note[1]),
NOTE_SEQUENCE.index(note[0]),
# 4-5: highest note in chord's octave and value
highest_note_chord[1],
NOTE_SEQUENCE.index(highest_note_chord[0]),
# 6-7: lowest note in chord's octave and value
lowest_note_chord[1],
NOTE_SEQUENCE.index(lowest_note_chord[0]),
# 8-10: average fret for three most recent chords
avg_frets[0],
avg_frets[1],
avg_frets[2],
# 11-12: fret and string for most recent occurrence note
recent_note[0],
recent_note[1],
# 13-20: string and fret for four most recent notes
preceding_notes[0][0],
preceding_notes[0][1],
preceding_notes[1][0],
preceding_notes[1][1],
preceding_notes[2][0],
preceding_notes[2][1],
preceding_notes[3][0],
preceding_notes[3][1],
# 21: number of chords played since last four notes
_chords_for_notes(4, preceding, fwd=False),
# 22-23: number of notes in previous two chords
num_notes_prev_chord,
num_notes_prev_chord_2,
# 24-29: booleans indicating whether string are in use
int(0 in current_chord),
int(1 in current_chord),
int(2 in current_chord),
int(3 in current_chord),
int(4 in current_chord),
int(5 in current_chord),
# 30-47: all string/fret combinations for the current note
# **ADDED** each third entry indicates whether combo is real
# **ADDED** supports up to 24 real frets, so 6 locations
fret_string_combos[0],
fret_string_combos[1],
fret_string_combos[2],
fret_string_combos[3],
fret_string_combos[4],
fret_string_combos[5],
fret_string_combos[6],
fret_string_combos[7],
fret_string_combos[8],
fret_string_combos[9],
fret_string_combos[10],
fret_string_combos[11],
fret_string_combos[12],
fret_string_combos[13],
fret_string_combos[14],
fret_string_combos[15],
fret_string_combos[16],
fret_string_combos[17],
# 48-49: number of notes in next two chords
num_notes_next_chord,
num_notes_next_chord_2,
# 50-61: octave and note for next six notes
NOTE_SEQUENCE.index(following_notes[0][0]),
following_notes[0][1],
NOTE_SEQUENCE.index(following_notes[1][0]),
following_notes[1][1],
NOTE_SEQUENCE.index(following_notes[2][0]),
following_notes[2][1],
NOTE_SEQUENCE.index(following_notes[3][0]),
following_notes[3][1],
NOTE_SEQUENCE.index(following_notes[4][0]),
following_notes[4][1],
NOTE_SEQUENCE.index(following_notes[5][0]),
following_notes[5][1],
# 62: number of chords between current note and next six notes
_chords_for_notes(6, following, fwd=True),
# 63-65: fret/string furthest from body for limiting note
minimal_fret_limiting_note,
minimal_string_limiting_note,
limiting_note_flag,
# 66: number of chords until next limiting note
to_limiting_note,
)
sample = (inputs, tuple(bits))
LOG.debug('Yielding sample: {sample}'.format(sample=sample))
yield sample
