!pip install music21

import itertools import random from music21 import * # python musicology import numpy as np # used essentially to transpose arrays for plotting import matplotlib.pyplot as plt # plot cellular automata random.seed(487638) # to make sure random processes are consistent between runs def create_ca1D(length, init, rules): """ Generates a cellular automata array of n rows from initial conditions and a rule set defined as a list of tuples generating ones. Arguments: length: positive integer describing the length of the cellular automata (number of simulations) init: a list of zeros and ones whose length specifies to the width of the cellular automata rules: a list of tuples or lists specifying a pattern in the previous state generating a one in the current state Returns: a 2D array of zeros and ones describing the cellular automata """ ncells = len(init) array = [[0] * ncells for _ in range(length)] # * crée des copies array[0] = init for i in range(1, length): for j in range(ncells): if j != (ncells - 1): ca_at = (array[i-1][j-1], array[i-1][j], array[i-1][j+1]) else: ca_at = (array[i-1][j-1], array[i-1][j], array[i-1][0]) if ca_at in rules: array[i][j] = 1 return(array) def strip_ca1D(array, limits): """ Selects a strip in a cellular automata array. Arguments: array: a list of equal-length lists of zeros and ones describing the cellular automata (usually the output of the `create_ca1D()` function) limits: a list of lists of 2 items describing the limits of the strips in the width of `array` Returns: a list of 2D arrays of zeros and ones describing cellular automata """ trim_indices = list(range(limits[0], limits[1])) array_trim = [] for i in range(len(array)): trim_i = [] for j in trim_indices: trim_i.append(array[i][j]) array_trim.append(trim_i) return(array_trim) def ca1D_to_stream(array, notes, durations, key_ = None): """ Maps a cellular automata array to notes and durations. Arguments: array: a list of equal-length lists of zeros and ones describing the cellular automata (usually the output of the `stip_ca1D()` function) notes: a list of notes in the form of "C3", "A5", "F4", etc., equal to the width (second dimension) of `array` durations: a list of durations in quarter-lengths key_: Optional; A key signature to add to the stream Returns: a music21 stream """ nevents = len(array) ncells = len(array[0]) durations_iterator = itertools.cycle(durations) stream_ca = stream.Stream() if key_ is not None: stream_ca.keySignature = key.Key(key_) for i in range(nevents): notes_i = [] duration_i = next(durations_iterator) for j in range(ncells): if array[i][j] == 1: notes_i.append(notes[j]) if len(notes_i) == 0: stream_ca.append(note.Rest(quarterLength = duration_i)) elif len(notes_i) == 1: stream_ca.append(note.Note(notes_i[0], quarterLength = duration_i)) else: stream_ca.append(chord.Chord(notes_i, quarterLength = duration_i)) return(stream_ca) def chords_to_notes(stream_, select = 'lowest'): """ Scans a music21 stream to replace chords by a single note of the chord (lowest, highest or random). Arguments: stream_: a music21 stream select: a string among ['lowest', 'highest', 'random'] describing which note in the chord will replace the chord Returns: a music21 stream """ chordless = stream.Stream() for i in stream_.iter().notesAndRests: if type(i) == type(chord.Chord()): if select == 'highest': n = i.notes[-1] elif select == 'lowest': n = i.notes[0] elif select == 'random': n = random.sample(i.notes, k = 1) else: print("select must be 'high', 'low' or 'random'") else: n = i chordless.append(n) return(chordless)

ca1D_rules = dict({ '018': [(1, 0, 0), (0, 0, 1)], # the one used in the video '022': [(1, 0, 0), (0, 1, 0), (0, 0, 1)], '030': [(1, 0, 0), (0, 1, 1), (0, 1, 0), (0, 0, 1)], '045': [(1, 0, 1), (0, 1, 1), (0, 1, 0), (0, 0, 0)], '054': [(1, 0, 1), (1, 0, 0), (0, 1, 0), (0, 0, 1)], '060': [(1, 0, 1), (1, 0, 0), (0, 1, 1), (0, 1, 0)], '073': [(1, 1, 0), (0, 1, 1), (0, 0, 0)], '102': [(1, 1, 0), (1, 0, 1), (0, 1, 0), (0, 0, 1)], '105': [(1, 1, 0), (1, 0, 1), (0, 1, 1), (0, 0, 0)], '110': [(1, 1, 0), (1, 0, 1), (0, 1, 1), (0, 1, 0), (0, 0, 1)], '126': [(1, 1, 0), (1, 0, 1), (1, 0, 0), (0, 1, 1), (0, 1, 0), (0, 0, 1)], '150': [(1, 1, 1), (1, 0, 0), (0, 1, 0), (0, 0, 1)] }) # 256 rule sets http://atlas.wolfram.com/01/01/

width = 50 # height of domains length = 24 # length of domains init = [0] * width # initial condition with only zeroes, but... init[width // 2] = 1 # altered with a one (or true, or turned on) cell in the middle fig, axes = plt.subplots(2, 6, figsize = (10, 5)) fig.subplots_adjust(hspace=0.5) axes = axes.flatten() for i, rule in enumerate(ca1D_rules.keys()): ca_i = create_ca1D(length, init, ca1D_rules[rule]) axes[i].matshow(np.array(ca_i).transpose(), cmap ="binary") axes[i].invert_yaxis() axes[i].set_title('rule ' + rule) axes[i].axis('off')

# Generate cells ca1_rule = ca1D_rules['150'] width1 = 200 length1 = 136 init = [0] * width1 init[width1 // 2] = 1 ca1 = create_ca1D(length1, init, ca1_rule) # select portions of the grid trimlimits1 = [ [width1//2 - 3, width1//2 + 3], # guitar [width1//2 - 15, width1//2 - 8] # bass guitar ] # plot fig, ax = plt.subplots(figsize = (5, 5)) ax.matshow(np.array(ca1).transpose(), cmap ="binary") ax.invert_yaxis() ax.tick_params(axis='both', labelsize=10) for i in range(len(trimlimits1)): rect = plt.Rectangle( (0, trimlimits1[i][0]), width = length1, height = trimlimits1[i][1] - trimlimits1[i][0], color = '#38A0A790' ) ax.add_patch(rect) ax.arrow(x=5, y=126, dx=0, dy=-15, width=0.5) ax.arrow(x=5, y=65, dx=0, dy=15, width=0.5) ax.text(2, 129, "Guitar", fontsize=10) ax.text(2, 58, "Bass", fontsize=10);

# Generate cells ca2_rule = ca1D_rules['018'] width2 = 200 length2 = 136 init = random.choices([0, 1], weights=[0.9, 0.1], k=width2) ca2 = create_ca1D(length2, init, ca2_rule) # select portions of the grid trimlimits2 = [ [110, 116], # drum kit ] # plot fig, ax = plt.subplots(figsize = (5, 5)) ax.matshow(np.array(ca2).transpose(), cmap ="binary") ax.invert_yaxis() ax.tick_params(axis='both', labelsize=10) rect = plt.Rectangle( (0, trimlimits2[0][0]), width = length2, height = trimlimits2[0][1] - trimlimits2[0][0], color = '#38A0A790' ) ax.add_patch(rect);

array1_trim = strip_ca1D(ca1, limits = trimlimits1[0]) array2_trim = strip_ca1D(ca1, limits = trimlimits1[1]) array3_trim = strip_ca1D(ca2, limits = trimlimits2[0])

arrays_trim = [array1_trim, array2_trim, array3_trim] fig, axs = plt.subplots(len(arrays_trim), 1, figsize = (12, 5)) for i, a in enumerate(arrays_trim): axs[i].matshow(np.array(a).transpose(), cmap ="binary") axs[i].invert_yaxis() axs[i].set_ylabel('track ' + str(i+1), rotation=0, labelpad=30)

# Guitar track1 = ca1D_to_stream( array = array1_trim, notes = ['C4', 'D4', 'Eb4', 'F4', 'G4', 'Ab4', 'Bb4'], durations = [0.5, 0.5, 1, 2, 1, 1, 0.5, 1.5] ) # Bass track2 = ca1D_to_stream( array = array2_trim, notes = ['C3', 'D3', 'Eb3', 'F3', 'G3', 'Ab3', 'Bb3'], durations = [1, 1, 2, 0.5, 0.5, 0.5, 0.5, 2] ) # Drums track3 = ca1D_to_stream( array = array3_trim, notes = ['C3', 'D3', 'Eb3', 'F3', 'G3', 'Ab3', 'Bb3'], durations = [2, 1, 1, 0.5, 0.5, 1, 1, 1] ).transpose('P5')

track2.show('midi')

track2_chordless = chords_to_notes(track2, select='random')

piece = stream.Stream() piece.insert(track1) piece.insert(track2_chordless) piece.insert(track3) piece.show('midi')

piece.write('midi', 'piece.midi')