def melodic_arch(score: stream.Stream, phrase_length: int):
total_phrases = 0 #total number of phrases
sum_pitch_height = [
0 for i in range(phrase_length)
] #sum of heights for each note position, measured in semitones above middle C
phrase = [] #phrase is empty at beginning of piece
for n in score.recurse().notesAndRests:
if isinstance(n, chord.Chord):
n = max(n)
if n.tie and (n.tie.type == 'stop' or n.tie.type
== 'continue'): #do not count a tied note more than once
continue
if n.isRest or (len(n.expressions) != 0
and 'fermata' == n.expressions[0].name):
if len(phrase) == phrase_length:
total_phrases += 1
for i in range(phrase_length):
sum_pitch_height[
i] += phrase[i].pitch.ps - 60 #60 is middle C
phrase = []
else:
phrase.append(n)
#if reached end of score, check the last phrase is of desired length
if len(phrase) == phrase_length:
total_phrases += 1
for i in range(phrase_length):
sum_pitch_height[i] += phrase[i].pitch.ps - 60
if total_phrases == 0:
return None
return [height / total_phrases for height in sum_pitch_height]
def avg_phrase_length(score: stream.Stream):
total_phrases = 0 #total number of phrases
length = 0 #phrase is empty at beginning of piece
phrase_lengths = [] #all the phrase lengths
for n in score.recurse().notesAndRests:
if isinstance(n, chord.Chord):
n = max(n)
if n.tie and (n.tie.type == 'stop' or n.tie.type
== 'continue'): #do not count a tied note more than once
continue
if n.isRest or (len(n.expressions) != 0
and 'fermata' == n.expressions[0].name):
phrase_lengths.append(length)
total_phrases += 1
length = 0
else:
length += 1
#reached end
if length != 0:
phrase_lengths.append(length)
total_phrases += 1
if total_phrases == 0:
return None
return sum(phrase_lengths) / total_phrases
def get_note_lengths(score: stream.Stream):
note_lengths = dict()
note_count = 0.0
for n in score.recurse().notesAndRests:
if isinstance(n, chord.Chord):
n = max(n)
if n.quarterLength not in note_lengths:
note_lengths[n.quarterLength] = 1
else:
note_lengths[n.quarterLength] += 1
note_count += 1.0
i = 0
vector = []
while i < 4:
i += 0.25
if i in note_lengths:
vector.append(note_lengths[i] / note_count)
else:
vector.append(0)
return vector
def nonharmonic_notes(score: stream.Stream):
key_sig = score.analyze('key')
certainty = key_sig.tonalCertainty()
notes_within_key = [p.name for p in key_sig.pitches]
for pitch in key_sig.pitches:
notes_within_key.extend(
[p.name for p in pitch.getAllCommonEnharmonics()])
total_notes = 0 #total number of notes
num_nonharmonic = 0 #total number of nonharmonic notes
for n in score.recurse().notes:
if isinstance(n, chord.Chord):
n = max(n)
if n.tie and (n.tie.type == 'stop' or n.tie.type
== 'continue'): #do not count a tied note more than once
continue
else:
if n.pitch.name not in notes_within_key:
num_nonharmonic += 1
total_notes += 1
if total_notes == 0:
return None
return (certainty, 1 - num_nonharmonic / total_notes)
def get_key(score: stream.Stream):
first_key = score.recurse().getElementsByClass(key.KeySignature)
if not first_key:
return 0
else:
return first_key[0].sharps
def get_meter(score: stream.Stream):
first_meter = score.recurse().getElementsByClass(meter.TimeSignature)
if not first_meter:
return (0, 0)
else:
return (first_meter[0].numerator, first_meter[0].denominator)
