def test_triad_generation(self):
diatonic_tonality = Tonality.create(ModalityType.Major, DiatonicTone("C"))
ret_types = [TertianChordType.Maj, TertianChordType.Min, TertianChordType.Min, TertianChordType.Maj,
TertianChordType.Maj,
TertianChordType.Min, TertianChordType.Dim]
for i in range(1, 8):
chord = TertianChordTemplate.get_triad(diatonic_tonality, i)
print(chord)
assert chord.chord_type.value == ret_types[i - 1]
def __init__(self,
secondary_chord_template,
diatonic_tonality,
secondary_tonality=None):
"""
Constructor.
:param secondary_chord_template: SecondaryChordTemplate
:param diatonic_tonality: DiatonicTonality (used in scale degree chord formation)
:param secondary_tonality: Used to represent denominator tonality
Note: The means for determining the secondary tonality is not necessarily clean. The standard technique
involves inferring the modality from the triad built on the i-th tone of the base modality. However,
the actual technique to be used can be a variable. The secondary_tonality argument is meant for cases where
the standard technique does not hold up - and provides a means for specifying the exact secondary tonality
when the standard technique does not apply.
"""
Chord.__init__(self, secondary_chord_template, diatonic_tonality)
# Build the tonality upon which the primary chord is based
diatonic_basis = self.diatonic_tonality.get_tone(
self.chord_template.secondary_scale_degree - 1)
# if no secondary modality specified?
# Use diatonic_tonality + secondary scale degree. Determine the triad type of the natural triad there, and
# if major, use major modality. If minor, use melodic minor modality. Otherwise flag an error.
if not self.chord_template.secondary_modality:
triad = TertianChordTemplate.get_triad(
diatonic_tonality, self.chord_template.secondary_scale_degree)
if triad:
modality = ModalityType.Major if triad.chord_type.value == TertianChordType.Maj or \
triad.chord_type.value == TertianChordType.Aug else \
ModalityType.MelodicMinor if triad.chord_type.value == TertianChordType.Min or \
triad.chord_type.value == TertianChordType.Dim else None
if modality is None:
raise Exception(
'Illegal secondary modality for secondary chord')
else:
raise Exception(
'Cannot determine secondary modality for secondary chord')
else:
modality = self.chord_template.secondary_modality
self.__secondary_tonality = Tonality.create(modality, diatonic_basis) \
if not secondary_tonality else secondary_tonality
# Create the principal chord
self.__primary_chord = self.chord_template.principal_chord_template.create_chord(
self.secondary_tonality)