Phaser

class auxjad.Phaser(contents: abjad.score.Container, *, step_size: Union[int, float, str, tuple, abjad.duration.Duration], max_steps: int = 1, forward_bias: float = 1.0, process_on_first_call: bool = False, remove_unterminated_ties: bool = True, omit_time_signatures: bool = False, boundary_depth: Optional[int] = None, maximum_dot_count: Optional[int] = None, rewrite_tuplets: bool = True, prettify_rewrite_meter: bool = True, extract_trivial_tuplets: bool = True, fuse_across_groups_of_beats: bool = True, fuse_quadruple_meter: bool = True, fuse_triple_meter: bool = True)

Takes an abjad.Container (or child class) as input and outputs an abjad.Selection with leaves shifted by a fixed amount. Subsequent calls apply further shifts.

Basic usage:

Calling the object will return an abjad.Selection generated by the phasing process. Each call of the object will shift the contents of the input container by a fixed amount given by step_size. Note that, by default, the first call outputs the initial container, with subsequent calls phasing it.

>>> container = abjad.Container(r"c'4 d'4 e'4 f'4")
>>> abjad.show(container)

>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        )
>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

The property current_window can be used to access the current window without moving the head forwards.

>>> notes = phaser.current_window()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

process_on_first_call:

The very first call will output the input container without processing it. To disable this behaviour and phase on the very first call, initialise the class with the keyword argument process_on_first_call set to True.

>>> container = abjad.Container(r"c'4 d'4 e'4 f'4")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        process_on_first_call=True,
...                        )
>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

step_size:

The argument step_size is used to step sizes for the phasing process. It takes a tuple or an abjad.Duration.

>>> container = abjad.Container(r"c'4 d'4 e'4 f'4")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 8),
...                        )
>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

Using as iterator:

The instances of Phaser can also be used as an iterator, which can then be used in a for loop to phase through a full cycle. Note that unlike the methods output_n() and output_all(), time signatures are added to each window returned by the shuffler. Use the function auxjad.mutate.remove_repeated_time_signatures() to clean the output when using Phaser in this way.

>>> container = abjad.Container(r"\time 3/4 c'4 d'4 e'4 ~ e'2.")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 4),
...                        )
>>> staff = abjad.Staff()
>>> for window in phaser:
...     staff.append(window)
>>> auxjad.mutate.remove_repeated_time_signatures(staff)
>>> abjad.show(staff)

Arguments and properties:

This class can take many optional keyword arguments during its creation. max_steps sets the maximum number of steps that can be applied for a single call, ranging between 1 and the input value (default is also 1); if max_steps is set to a value larger than 1, the number of steps at every call will be randomly chosen. forward_bias sets the chance of the process moving forward instead of backwards. It should range from 0.0 to 1.0 (default 1.0, which means the process can only move forwards. A value of 0.5 gives 50% chance of moving forwards while a value of 0.0 will result in the process moving only backwards). By default, when a logical tie is split in between windows, any unterminated ties will be removed; set remove_unterminated_ties to False to disable this behaviour. The properties boundary_depth, maximum_dot_count, and rewrite_tuplets are passed as arguments to abjad.Meter.rewrite_meter(), see its documentation for more information. By default, calling the object will first return the original container and subsequent calls will process it; set process_on_first_call to True and the looping process will be applied on the very first call. Setting the property omit_time_signatures to True will remove all time signatures from the output (False by default).

>>> container = abjad.Container(r"c'4 d'4 e'4 f'4")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(5, 8),
...                        max_steps=2,
...                        forward_bias=0.2,
...                        remove_unterminated_ties=True,
...                        omit_time_signatures=True,
...                        boundary_depth=0,
...                        maximum_dot_count=1,
...                        rewrite_tuplets=False,
...                        process_on_first_call=True,
...                        )
>>> phaser.step_size
5/8
>>> phaser.max_steps
2
>>> phaser.forward_bias
0.2
>>> phaser.remove_unterminated_ties
True
>>> phaser.omit_time_signatures
True
>>> phaser.boundary_depth
0
>>> phaser.maximum_dot_count
1
>>> phaser.rewrite_tuplets
False
>>> phaser.process_on_first_call
True

Use the properties below to change these values after initialisation.

>>> phaser.step_size = (1, 4)
>>> phaser.max_steps = 3
>>> phaser.forward_bias = 0.8
>>> phaser.remove_unterminated_ties = False
>>> phaser.omit_time_signatures = False
>>> phaser.boundary_depth = 1
>>> phaser.maximum_dot_count = 2
>>> phaser.rewrite_tuplets = True
>>> phaser.process_on_first_call = False
>>> phaser.step_size
1/4
>>> phaser.max_steps
3
>>> phaser.forward_bias
0.8
>>> phaser.remove_unterminated_ties
False
>>> phaser.omit_time_signatures
False
>>> phaser.boundary_depth
1
>>> phaser.maximum_dot_count
2
>>> phaser.rewrite_tuplets
True
>>> phaser.process_on_first_call
False

Setting forward_bias to 0.0:

Set forward_bias to 0.0 to move backwards instead of forwards (default is 1.0).

>>> container = abjad.Container(r"\time 3/8 c'8 d'8 e'8")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        )
>>> notes = phaser.output_n(3)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

>>> container = abjad.Container(r"\time 3/8 c'8 d'8 e'8")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        forward_bias=0.0,
...                        )
>>> notes = phaser.output_n(3)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

forward_bias between 0.0 and 1.0:

Setingt forward_bias to a value in between 0.0 and 1.0 will result in random steps being taken forward or backward, according to the bias.

>>> container = abjad.Container(r"c'4 d'4 e'4 f'4")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 4),
...                        forward_bias=0.5,
...                        )
>>> notes = phaser.output_n(5)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

max_steps:

Setting the keyword argument max_steps to a value larger than 1 will result in a random number of steps (between 1 and max_steps) being applied at each call.

>>> container = abjad.Container(r"c'8 d'8 e'8 f'8 g'8 a'8 b'8 c''8")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 8),
...                        max_steps=4,
...                        )
>>> notes = phaser.output_n(5)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

len():

The function len() can be used to get the total number of steps that are necessary to return to the initial container.

>>> container = abjad.Container(r"c'1")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        )
>>> len(phaser)
16
>>> container = abjad.Container(r"c'1")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 4),
...                        )
>>> len(phaser)
4
>>> container = abjad.Container(r"\time 3/4 c'2.")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 2),
...                        )
>>> len(phaser)
3

output_all():

To run through the whole process and output it as a single container, from the initial head position until the process outputs the single last element, use the method output_all().

>>> container = abjad.Container(r"\time 3/4 c'4. d'4.")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 4),
...                        )
>>> notes = phaser.output_all()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

cycle_back_to_first:

By default, output_all() will cycle back to the very first window. To stop at the iteration step just before looping back to the initial container, set the keyword argument cycle_back_to_first to False.

>>> container = abjad.Container(r"\time 3/4 c'4. d'4.")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 4),
...                        )
>>> notes = phaser.output_all(cycle_back_to_first=False)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

output_n():

To run through just part of the process and output it as a single container, starting from the initial head position, use the method output_n() and pass the number of iterations as argument.

>>> container = abjad.Container(r"c'4 d'4 e'4 f'4")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 32),
...                        )
>>> notes = phaser.output_n(3)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

tie_identical_pitches:

Both output_n() and output_all() methods can receive the keyword argument tie_identical_pitches, which will tie identical pitches across iterations of the process when set to True (default is False). Compare the output below with the example just above.

>>> container = abjad.Container(r"c'4 d'4 e'4 f'4")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 32),
...                        )
>>> notes = phaser.output_n(3, tie_identical_pitches=True)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

remove_unterminated_ties:

All methods that call the phasing process (__call__(), __next__(), output_all(), output_n()) remove unterminated ties at the end of a selection, which are a result of a logical tie being split at that point. Use the optional keyword argument remove_unterminated_ties=False when initialising the phaser to disable this behaviour.

>>> container = abjad.Container(r"c'4 d'4 e'4 f'4")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        process_on_first_call=True,
...                        remove_unterminated_ties=False,
...                        )
>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

Time signature changes:

This class handles time signature changes.

>>> container = abjad.Container(
...     r"\time 2/4 c'2 \time 3/8 d'4. \time 2/4 e'2"
... )
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 8),
...                        )
>>> notes = phaser.output_n(3)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

Indicators:

This class can handle dynamics and articulations too. When a logical tie is split into two during the phasing process, dynamics and articulations are passed on to both of them.

>>> container = abjad.Container(r"c'4-.\p\< d'4--\f e'4->\p f'4")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 8),
...                        )
>>> staff = abjad.Staff()
>>> notes = phaser.output_n(5)
>>> staff.append(notes)
>>> abjad.show(staff)

Slurs and hairpins:

Slurs and hairpins are also supported.

>>> container = abjad.Container(
...     r"c'2(\p\< d'4. e'8\f f'4\p\> g'2 a'4\pp)"
... )
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        )
>>> notes = phaser.output_n(5)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

Tip

The functions auxjad.mutate.remove_repeated_dynamics() and auxjad.mutate.reposition_clefs() can be used to clean the output and remove repeated dynamics and unnecessary clef changes.

Warning

Do note that some elements that span multiple notes (such as ottava indicators, manual beams, etc.) can become problematic when notes containing them are split into two. As a rule of thumb, it is always better to attach those to the music after the fading process has ended.

contents:

Use the contents property to read as well as overwrite the contents of the phaser. Notice that the phasing process will start from the beginning of the new container.

>>> container = abjad.Container(r"c'4 d'4 e'4 f'4")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        )
>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

>>> phaser.contents = abjad.Container(r"c'16 d'16 e'16 f'16 g'2.")
>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

Tweaking abjad.Meter.rewrite_meter():

This function uses the default logical tie splitting algorithm from abjad.Meter.rewrite_meter().

>>> container = abjad.Container(r"c'4. d'8 e'2")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        )
>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

Set boundary_depth to a different number to change its behaviour.

>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        boundary_depth=1,
...                        )
>>> notes = phaser()
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

Other arguments available for tweaking the output of abjad.Meter.rewrite_meter() are maximum_dot_count and rewrite_tuplets, which work exactly as the identically named arguments of abjad.Meter.rewrite_meter().

This class also accepts the arguments fuse_across_groups_of_beats, fuse_quadruple_meter, fuse_triple_meter, and extract_trivial_tuplets, which are passed on to auxjad.mutate.prettify_rewrite_meter() (the latter can be disabled by setting prettify_rewrite_meter to False). See the documentation of this function for more details on these arguments.

omit_time_signatures:

To disable time signatures altogether, initialise this class with the keyword argument omit_time_signatures set to True (default is False), or use the omit_time_signatures property after initialisation.

>>> container = abjad.Container(r"\time 3/4 c'4 d'4 e'4")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 8),
...                        omit_time_signatures=True,
...                        )
>>> notes = phaser.output_n(3)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

Tip

All methods that return an abjad.Selection will add an initial time signature to it. The output_n() and output_all() methods automatically remove repeated time signatures. When joining selections output by multiple method calls, use auxjad.mutate.remove_repeated_time_signatures() on the whole container after fusing the selections to remove any unecessary time signature changes.

Warning

This class can handle tuplets, but the output is often quite complex. Although the result will be rhythmically correct, consecutive tuplets are not fused together, and tuplets may be output off-beat. This functionality should be considered experimental.

>>> container = abjad.Container(r"\times 2/3 {c'8 d'8 e'8} d'2.")
>>> phaser = auxjad.Phaser(container,
...                        step_size=(1, 16),
...                        )
>>> notes = phaser.output_n(3)
>>> staff = abjad.Staff(notes)
>>> abjad.show(staff)

Methods

__call__()	Calls the phaser process for one iteration, returning an abjad.Selection.
__init__(contents, *, step_size[, …])	Initialises self.
__iter__()	Returns an iterator, allowing instances to be used as iterators.
__len__()	Returns the length of contents in terms of step_size.
__next__()	Calls the phaser process for one iteration, returning an abjad.Selection.
__repr__()	Returns interpreter representation of contents.
output_all(*[, cycle_back_to_first, …])	Goes through the whole phasing process and outputs a single abjad.Selection.
output_n(n, *[, tie_identical_pitches])	Goes through n iterations of the phasing process and outputs a single abjad.Selection.

Attributes

boundary_depth	Sets the argument boundary_depth of abjad.Meter.rewrite_meter().
contents	The abjad.Container to be phased.
current_window	Read-only property, returns the previously output selection.
extract_trivial_tuplets	Sets the argument extract_trivial_tuplets of auxjad.mutate.prettify_rewrite_meter().
forward_bias	The chance of the window moving forward instead of backwards.
fuse_across_groups_of_beats	Sets the argument fuse_across_groups_of_beats of auxjad.mutate.prettify_rewrite_meter().
fuse_quadruple_meter	Sets the argument fuse_quadruple_meter of auxjad.mutate.prettify_rewrite_meter().
fuse_triple_meter	Sets the argument fuse_triple_meter of auxjad.mutate.prettify_rewrite_meter().
max_steps	The maximum number of steps per operation.
maximum_dot_count	Sets the argument maximum_dot_count of abjad.Meter.rewrite_meter().
omit_time_signatures	When True, all time signatures will be omitted from the output.
pivot_point	Read-only property, returns the position of the pivot point.
prettify_rewrite_meter	Used to enable or disable the mutation auxjad.mutate.prettify_rewrite_meter() (default True).
process_on_first_call	If True then contents will be processed in the very first call.
remove_unterminated_ties	When True, the last element of the abjad.Selection returned by a call will have any ties removed.
rewrite_tuplets	Sets the argument rewrite_tuplets of abjad.Meter.rewrite_meter().
step_size	The size of each step when moving the pivot point.

__call__() → abjad.select.Selection

Calls the phaser process for one iteration, returning an abjad.Selection.

__init__(contents: abjad.score.Container, *, step_size: Union[int, float, str, tuple, abjad.duration.Duration], max_steps: int = 1, forward_bias: float = 1.0, process_on_first_call: bool = False, remove_unterminated_ties: bool = True, omit_time_signatures: bool = False, boundary_depth: Optional[int] = None, maximum_dot_count: Optional[int] = None, rewrite_tuplets: bool = True, prettify_rewrite_meter: bool = True, extract_trivial_tuplets: bool = True, fuse_across_groups_of_beats: bool = True, fuse_quadruple_meter: bool = True, fuse_triple_meter: bool = True) → None

Initialises self.

__iter__() → None

Returns an iterator, allowing instances to be used as iterators.

__len__() → int

Returns the length of contents in terms of step_size.

__next__() → abjad.select.Selection

Calls the phaser process for one iteration, returning an abjad.Selection.

__repr__() → str

Returns interpreter representation of contents.

property boundary_depth: Optional[int]

Sets the argument boundary_depth of abjad.Meter.rewrite_meter().

property contents: abjad.score.Container

The abjad.Container to be phased.

property current_window: abjad.select.Selection

Read-only property, returns the previously output selection.

property extract_trivial_tuplets: bool

Sets the argument extract_trivial_tuplets of auxjad.mutate.prettify_rewrite_meter().

property forward_bias: float

The chance of the window moving forward instead of backwards. It should range from 0.0 to 1.0 (default 1.0, which means the window can only move forwards. A value of 0.5 gives 50% chance of moving forwards while a value of 0.0 will move the window only backwards).

property fuse_across_groups_of_beats: bool

Sets the argument fuse_across_groups_of_beats of auxjad.mutate.prettify_rewrite_meter().

property fuse_quadruple_meter: bool

Sets the argument fuse_quadruple_meter of auxjad.mutate.prettify_rewrite_meter().

property fuse_triple_meter: bool

Sets the argument fuse_triple_meter of auxjad.mutate.prettify_rewrite_meter().

property max_steps: int

The maximum number of steps per operation.

property maximum_dot_count: Optional[int]

Sets the argument maximum_dot_count of abjad.Meter.rewrite_meter().

property omit_time_signatures: bool

When True, all time signatures will be omitted from the output.

output_all(*, cycle_back_to_first: bool = True, tie_identical_pitches: bool = False) → abjad.select.Selection

Goes through the whole phasing process and outputs a single abjad.Selection.

output_n(n: int, *, tie_identical_pitches: bool = False) → abjad.select.Selection

Goes through n iterations of the phasing process and outputs a single abjad.Selection.

property pivot_point: abjad.duration.Duration

Read-only property, returns the position of the pivot point.

property prettify_rewrite_meter: bool

Used to enable or disable the mutation auxjad.mutate.prettify_rewrite_meter() (default True).

property process_on_first_call: bool

If True then contents will be processed in the very first call.

property remove_unterminated_ties: bool

When True, the last element of the abjad.Selection returned by a call will have any ties removed. This means that splitted logical ties will not tie accross multiple calls.

property rewrite_tuplets: bool

Sets the argument rewrite_tuplets of abjad.Meter.rewrite_meter().

property step_size: abjad.duration.Duration

The size of each step when moving the pivot point.