def generate_chord(key):
"""Returns a chord (list of notes)."""
if keys.is_major_key(key):
kp_data = probdata.KP_MAJOR_KEY_PROFILE_DATA
else:
kp_data = probdata.KP_MINOR_KEY_PROFILE_DATA
result = []
for scale_degree in range(12):
x = random.uniform(0.0, 1.0)
if x < kp_data[scale_degree]:
result.append(scale_degree)
return [60 + (key[0] + scale_degree) % 12 for scale_degree in result]
def generate_note(previous_note, central_note, key):
"""Returns a note value generated from range, key, and proximity profiles.
`previous_note` is the note value of the note that the generated note
will follow.
`central_note` is the mean note value of the musical piece we are
generating a note for.
`key` is a (tonic, is_major) tuple where `tonic` is the base note of the
key, and `is_major` is 1 if the key is a major key and 0 otherwise.
"""
# Select the major or minor key profile based on the key.
if keys.is_major_key(key):
key_profile_data = probdata.ESSEN_MAJOR_KEY_PROFILE_DATA
else:
key_profile_data = probdata.ESSEN_MINOR_KEY_PROFILE_DATA
kp = probabilities.build_key_profile(key_profile_data, key)
# Get the range and proximity profiles from `probdata`.
rp_data = probdata.RANGE_PROFILE_DATA
rp = probabilities.build_distance_profile(rp_data, central_note)
pp_data = probdata.PROXIMITY_PROFILE_DATA
pp = probabilities.build_distance_profile(pp_data, previous_note)
# Generate a list of all notes to consider.
notes = range(settings.MAX_NOTE + 1)
# Calculate the probability of each possible next note.
# The resulting table is indexed by note value.
weights = [rp(i) * pp(i) * kp(i) for i in notes]
# Select a note randomly in proportion to its weight.
result_note = None
x = random.uniform(0.0, sum(weights))
for note, weight in enumerate(weights):
if x < weight:
result_note = note
break
else:
x = x - weight
return result_note