IntervalQuality

IntervalQuality(name: str, rel_number: float)

One of the nineteen interval qualities; see QUALITIES.

>>> QUALITIES[0]
IntervalQuality("perfect", 0)
>>> QUALITIES[0.5] + 1
IntervalQuality("augmented-from_maj_min", 1.5)

Attributes

Name	Description
name
rel_number
chromatic_modifier	Half-steps above the diatonic base of the interval.
abbr	The first three letters of each word of the name, as TonalVector.from_string accepts them.

Methods

Name	Description
augment	The quality halfsteps half-steps wider, in the same family.
diminish	The quality halfsteps half-steps narrower, in the same family.
__add__	augment, as an operator.
__sub__	diminish, as an operator.
__str__	The name in words, without the family suffix.
__repr__

augment

augment(halfsteps: int = 1)

The quality halfsteps half-steps wider, in the same family.

>>> QUALITIES[0].augment()
IntervalQuality("augmented-from_perfect", 1)
>>> QUALITIES[0.5].augment(2)
IntervalQuality("dbl_augmented-from_maj_min", 2.5)

Raises ValueError past the ends of the table (quadruply augmented or diminished), as TonalVector.from_string does for the same overflow:

>>> QUALITIES[4.5].augment()
Traceback (most recent call last):
...
ValueError: 5.5 is beyond the supported range of interval qualities (-4.5 to 4.5).

diminish

diminish(halfsteps: int = 1)

The quality halfsteps half-steps narrower, in the same family.

>>> QUALITIES[0.5].diminish(), QUALITIES[0].diminish()
(IntervalQuality("minor", -0.5), IntervalQuality("diminished-from_perfect", -1))

__add__

__add__(halfsteps: int)

augment, as an operator.

>>> QUALITIES[-0.5] + 1
IntervalQuality("major", 0.5)

__sub__

__sub__(halfsteps: int)

diminish, as an operator.

>>> QUALITIES[0.5] - 2
IntervalQuality("diminished-from_maj_min", -1.5)

__str__

__str__()

The name in words, without the family suffix.

>>> str(QUALITIES[-3])
'trpl diminished'

__repr__

__repr__()