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MelodyMarkov.py
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MelodyMarkov.py
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import random;
class MelodyMarkov:
def __init__(self,notes,steps=2):
self.steps = steps;
self.phrases = [];
self.markovChain = {};
self.generateMarkovChain(notes);
#takes an array of midi values
def generateMarkovChain(self,notes):
for idx in range(len(notes)):
listToTuple = [];
for stepIdx in range(self.steps,0, -1):
listToTuple.append(notes[idx - stepIdx]);
key = tuple(listToTuple);
pitchObject = notes[idx];
if self.markovChain.get(key,False):
self.markovChain[key].append(pitchObject)
else:
self.markovChain[key] = [pitchObject]
return self.markovChain;
def generateTupleKey(self,phrase,currentIndex,repeat=False):
listToTuple = [];
for j in range(self.steps, 0, -1):
offset = 1 if repeat else j;
listToTuple.append(phrase[currentIndex-offset]);
return tuple(listToTuple);
def appendToPhrase(self,tupleKey,phrase):
if self.markovChain.get(tupleKey,False):
randomNote = random.choice(self.markovChain[tupleKey]);
phrase.append(randomNote);
return True;
return False;
def generateMelody(self, phraseLength=1000, endless=False):
randomStartingTuple = self.getStartingTuple();
phrase = list(randomStartingTuple);
for i in range(1, phraseLength):
tupleKey = self.generateTupleKey(phrase,i);
if self.appendToPhrase(tupleKey,phrase):
continue;
repeatedNote = self.generateTupleKey(phrase,i,True);
if self.appendToPhrase(repeatedNote,phrase):
continue;
else:
if (endless):
if (not self.appendToPhrase(randomStartingTuple,phrase)):
break;
self.phrases.append(phrase);
return phrase;
def getStartingTuple(self):
randomStartingTuple = random.choice(self.markovChain.keys());
length = len(self.markovChain[randomStartingTuple]);
return randomStartingTuple;
def getPitchDuration(notes, idx):
if idx:
return notes[idx].offset - notes[idx-1].offset
else:
return notes[idx].offset