In [2]:
url = 'https://analyse.hfm-weimar.de/database/03/BeLuva_Op18_1-6_1-4_StringQuar_003_00104.xml'
music = converter.parse(url)
music.show()
(version 2022_01_03)
This tutorial explains how to refine the motif search to search not only for sequences of notes, but for sequences of notes with a specific rhythm.
The tutorial follows on from the "Tutorial Notes Advanced Part 1: Motif search at Josquin". The first steps are therefore identical. However, we have chosen another music example: a composition by a composer in whom the use of motifs plays a particularly important role: the first movement of the String Quartet Op. 18, No. 1, by Ludwig van Beethoven.
from music21 import *
url = 'https://analyse.hfm-weimar.de/database/03/BeLuva_Op18_1-6_1-4_StringQuar_003_00104.xml'
music = converter.parse(url)
music.show()
In order to search for repetitions of the opening motive in exactly the same rhythmic structure, the melodic pattern must now be defined in rhythmic terms as well:
StreamMot=stream.Stream()
StreamMot.append(note.Note('F', quarterLength=1.5))
StreamMot.append(note.Note('G', quarterLength= 0.25))
StreamMot.append(note.Note('F', quarterLength=0.25))
StreamMot.append(note.Note('E', quarterLength=0.5))
StreamMot.append(note.Note('F', quarterLength=0.5))
# The addition 'quaterLength= ' refers to multiples of a quarter note = 1.
StreamMot.show()
s = music.recurse().notes
# The search is now created with the command 'search.noteNameRhythmicSearch'.
p = search.noteNameRhythmicSearch(s, StreamMot)
p
[75, 815, 821, 1933, 2847, 2853, 3202, 3735, 3741, 3908, 3914, 4011, 4017]
As expected, the motif appears relatively often: exactly 13 times!
print(len(p))
13
Determining the exact position in the score (measure, beat, voice):
counter=1
for Position in p:
startingNote=s[Position]
startingMeasure = startingNote.measureNumber
startingBeat = startingNote.beat
startingPart = startingNote.getContextByClass('Part')
print('%2s %3s %3s' %(counter, startingNote.nameWithOctave, startingMeasure), startingBeat, startingPart)
counter+=1
1 F5 22 1.0 <music21.stream.Part Violin> 2 F5 179 1.0 <music21.stream.Part Violin> 3 F5 181 1.0 <music21.stream.Part Violin> 4 F4 181 1.0 <music21.stream.Part Violin> 5 F3 179 1.0 <music21.stream.Part Viola> 6 F3 181 1.0 <music21.stream.Part Viola> 7 F4 300 1.0 <music21.stream.Part Viola> 8 F2 179 1.0 <music21.stream.Part Violoncello> 9 F2 181 1.0 <music21.stream.Part Violoncello> 10 F3 262 1.0 <music21.stream.Part Violoncello> 11 F3 264 1.0 <music21.stream.Part Violoncello> 12 F2 302 1.0 <music21.stream.Part Violoncello> 13 F2 304 1.0 <music21.stream.Part Violoncello>
Marking in the score - we take the prominent position in M. 179-181, which appears in several parts at once:
for found in p:
for ffound in range(len(StreamMot)):
s[found+ffound].lyric = '*'
s[found+ffound].style.color='red'
music.measures(179,181).show()
Unfortunately, Beethoven very often did not notate the beginning of the motif as dotted crotchets, but rather as tied crotchets + eighth notes. Unfortunately, this notation is not included in the 13 search results.
To take these tied notes into account, a trick must be used in music21:
The command "stripTies" replaces two tied notes with a note of the same length. By this method, the motifs with overtied note values can now be determined.
music_tie = converter.parse(url).stripTies(inPlace=True)
s1 = music_tie.recurse().notes
music_tie.show()
# Shows the score without tied notes.
len(s)
# = Number of notes, if tied notes are counted separately.
4049
len(s1)
# = Number of notes, without separate counting of tied notes.
3918
So by breaking up the ties there are (4049-3918=) 131 less notes!!!
p1 = search.noteNameRhythmicSearch(s1, StreamMot)
If we list the motifs before and after deletion of the ties, it becomes clear that 22 instances have been added now:
print('Without merging tied notes:', len(p))
print('With merging tied notes:', len(p1))
Without merging tied notes: 13 With merging tied notes: 35
Now we determine the exact positions of the individual motifs and mark the places in the score:
counter=1
for Position in p1:
startingNote=s1[Position]
startingMeasure = startingNote.measureNumber
startingBeat = startingNote.beat
startingPart = startingNote.getContextByClass('Part')
print('%2s %3s %3s' %(counter, startingNote.nameWithOctave, startingMeasure), startingBeat, startingPart)
counter+=1
1 F4 1 1.0 <music21.stream.Part Violin> 2 F4 3 1.0 <music21.stream.Part Violin> 3 F5 5 1.0 <music21.stream.Part Violin> 4 F4 9 1.0 <music21.stream.Part Violin> 5 F4 11 1.0 <music21.stream.Part Violin> 6 F5 13 1.0 <music21.stream.Part Violin> 7 F5 22 1.0 <music21.stream.Part Violin> 8 F5 159 1.0 <music21.stream.Part Violin> 9 F4 162 1.0 <music21.stream.Part Violin> 10 F5 179 1.0 <music21.stream.Part Violin> 11 F5 181 1.0 <music21.stream.Part Violin> 12 F5 183 1.0 <music21.stream.Part Violin> 13 F5 294 1.0 <music21.stream.Part Violin> 14 F4 1 1.0 <music21.stream.Part Violin> 15 F4 3 1.0 <music21.stream.Part Violin> 16 F4 9 1.0 <music21.stream.Part Violin> 17 F4 11 1.0 <music21.stream.Part Violin> 18 F4 181 1.0 <music21.stream.Part Violin> 19 F3 1 1.0 <music21.stream.Part Viola> 20 F3 3 1.0 <music21.stream.Part Viola> 21 F3 9 1.0 <music21.stream.Part Viola> 22 F3 11 1.0 <music21.stream.Part Viola> 23 F3 179 1.0 <music21.stream.Part Viola> 24 F3 181 1.0 <music21.stream.Part Viola> 25 F4 300 1.0 <music21.stream.Part Viola> 26 F3 1 1.0 <music21.stream.Part Violoncello> 27 F3 3 1.0 <music21.stream.Part Violoncello> 28 F3 9 1.0 <music21.stream.Part Violoncello> 29 F3 11 1.0 <music21.stream.Part Violoncello> 30 F2 179 1.0 <music21.stream.Part Violoncello> 31 F2 181 1.0 <music21.stream.Part Violoncello> 32 F3 262 1.0 <music21.stream.Part Violoncello> 33 F3 264 1.0 <music21.stream.Part Violoncello> 34 F2 302 1.0 <music21.stream.Part Violoncello> 35 F2 304 1.0 <music21.stream.Part Violoncello>
for found in p1:
for ffound in range(len(StreamMot)):
s1[found+ffound].lyric = '*'
s1[found+ffound].style.color='red'
music_tie.show()
In Music21, a command can be programmed to search for every chromatic transposition of a motif. First we need the following command:
def pitchClassEqual(n1, n2):
if not hasattr(n1, 'pitch'):
return False
if not hasattr(n2, 'pitch'):
return False
if n1.pitch.pitchClass == n2.pitch.pitchClass:
return True
else:
return False
In the following, we will search for the motif starting at every chromatic pitch (and their respective enharmonic equivalents). To do this, one must create an algorithm that is repeated 12 times. A second loop helps to enter the information from each repetition into the results list.
results = []
zähler = 1
# The results must be entered in an extra list ("results").
# The "counter" simplifies the enumeration of the tones, if you want to show them one after the other.
for egal in range(12):#Suche 12 Mal
s_len = [StreamMot.notes[i].name for i in range (len(StreamMot.notes))]
print("------------\nSearching for:", *s_len, sep=' ')
p = search.streamSearchBase(s, StreamMot, algorithm=pitchClassEqual)
for notePosition in p:
startingNote=s[notePosition]
startingMeasure = startingNote.measureNumber
startingBeat = startingNote.beat
startingPart = startingNote.getContextByClass('Part')
results.append(notePosition)
print('%2s %3s %3s' %(zähler, startingNote.nameWithOctave, startingMeasure), startingBeat, startingPart.id)
zähler+=1
[n.transpose(1, inPlace=True) for n in StreamMot]
# After each search, everything is transposed up half a tone
------------ Searching for: F G F E F 1 F4 1 2.0 Violin 2 F4 3 2.0 Violin 3 F5 5 2.0 Violin 4 F4 9 2.0 Violin 5 F4 11 2.0 Violin 6 F5 13 2.0 Violin 7 F5 19 1.0 Violin 8 F5 22 1.0 Violin 9 F5 159 2.0 Violin 10 F4 162 2.0 Violin 11 F5 179 1.0 Violin 12 F5 181 1.0 Violin 13 F5 183 2.0 Violin 14 F5 282 1.0 Violin 15 F5 294 2.0 Violin 16 F4 312 1.0 Violin 17 F4 1 2.0 Violin 18 F4 3 2.0 Violin 19 F4 9 2.0 Violin 20 F4 11 2.0 Violin 21 F4 181 1.0 Violin 22 F4 287 1.0 Violin 23 F5 308 3.5 Violin 24 F3 1 2.0 Viola 25 F3 3 2.0 Viola 26 F3 9 2.0 Viola 27 F3 11 2.0 Viola 28 F3 179 1.0 Viola 29 F3 181 1.0 Viola 30 F4 300 1.0 Viola 31 F3 1 2.0 Violoncello 32 F3 3 2.0 Violoncello 33 F3 9 2.0 Violoncello 34 F3 11 2.0 Violoncello 35 F2 179 1.0 Violoncello 36 F2 181 1.0 Violoncello 37 F3 262 1.0 Violoncello 38 F3 264 1.0 Violoncello 39 F2 265 1.0 Violoncello 40 F3 266 1.75 Violoncello 41 F3 266 2.75 Violoncello 42 F2 267 1.0 Violoncello 43 F3 268 1.75 Violoncello 44 F3 268 2.75 Violoncello 45 F2 302 1.0 Violoncello 46 F2 304 1.0 Violoncello ------------ Searching for: F# G# F# F F# 47 G-5 155 2.0 Violin ------------ Searching for: G A G F# G 48 G5 15 2.0 Violin 49 G5 24 1.0 Violin 50 G4 284 1.0 Violin 51 G4 25 2.0 Violin 52 G3 285 1.0 Viola 53 G4 72 1.0 Violoncello 54 G4 74 1.0 Violoncello 55 G4 76 1.0 Violoncello ------------ Searching for: G# B- G# G G# 56 A-5 143 1.0 Violin 57 A-4 161 2.0 Violin 58 A-4 143 2.0 Violin 59 A-4 164 2.0 Violin 60 A-4 141 1.0 Viola 61 A-3 142 1.0 Violoncello ------------ Searching for: A B A G# A ------------ Searching for: B- C B- A B- 62 B-5 131 1.0 Violin 63 B-5 152 2.0 Violin 64 B-4 207 1.0 Violin 65 B-4 283 2.0 Violin 66 B-4 292 1.0 Violin 67 B-4 123 1.0 Violin 68 B-4 131 2.0 Violin 69 B-4 187 2.0 Violin 70 B-3 207 1.0 Violin 71 B-4 286 1.0 Violin 72 B-3 119 1.0 Viola 73 B-3 121 1.0 Viola 74 B-4 130 1.0 Viola 75 B-2 119 1.0 Violoncello 76 B-2 121 1.0 Violoncello 77 B-3 129 1.0 Violoncello ------------ Searching for: B C# B B- B ------------ Searching for: C D C B C 78 C6 26 1.0 Violin 79 C5 301 1.0 Violin 80 C5 311 1.0 Violin 81 C4 21 2.0 Violin 82 C4 288 1.0 Violin 83 C4 290 1.0 Violin 84 C3 289 1.0 Viola 85 C3 291 1.0 Viola 86 C3 30 1.0 Violoncello 87 C3 32 1.0 Violoncello 88 C3 34 1.0 Violoncello 89 C3 36 1.0 Violoncello 90 C3 101 1.0 Violoncello 91 C3 103 1.0 Violoncello 92 C2 104 1.0 Violoncello 93 C3 105 1.75 Violoncello 94 C3 105 2.75 Violoncello 95 C2 106 1.0 Violoncello 96 C3 107 1.75 Violoncello 97 C3 107 2.75 Violoncello 98 C4 233 1.0 Violoncello 99 C4 235 1.0 Violoncello 100 C4 237 1.0 Violoncello ------------ Searching for: C# E- C# C C# 101 D-6 151 2.0 Violin 102 D-5 154 2.0 Violin 103 D-5 156 2.0 Violin 104 D-5 163 2.0 Violin 105 D-3 198 1.0 Viola 106 D-3 200 1.0 Viola 107 D-3 202 1.0 Viola 108 D-3 204 1.0 Viola 109 D-3 206 1.0 Viola ------------ Searching for: D E D C# D 110 D5 126 1.0 Violin ------------ Searching for: E- F E- D E- 111 E-6 137 1.0 Violin 112 E-5 135 2.0 Violin 113 E-3 41 1.0 Viola 114 E-3 43 1.0 Viola 115 E-3 45 1.0 Viola 116 E-4 137 2.0 Viola ------------ Searching for: E F# E E- E
print(len(results))
116
Strikingly, we have found 116 occurrences of the motif on different tone levels.
Search in sheet music files of your choice for motives you suspect there and for their transpositions! For example, in sonata movements, look for prominent motives from the first or second theme.