Patterns

Pattern classes for generating sequences of values.

This module provides pattern classes inspired by SuperCollider's pattern system for generating sequences, random selections, and non-repeating random selections from lists of values.

Classes:

Name	Description
Pseq	Sequential pattern that cycles through a list
Prand	Random pattern that selects randomly from a list
Pxrand	Exclusive random pattern that avoids immediate repetition

PVoiceAllocator

Voice allocator for managing polyphonic voice assignments.

PVoiceAllocator keeps track of busy and free voices for polyphonic synthesis, allowing for efficient voice allocation and deallocation.

Attributes:

Name	Type	Description
num_voices		Total number of voices available
busy_list		List tracking the status of each voice (-1 for free, otherwise holds the note number)

__init__(num_voices)

Voice allocator for managing polyphonic voice assignments.

PVoiceAllocator keeps track of busy and free voices for polyphonic synthesis, allowing for efficient voice allocation and deallocation.

get_free_voice(note)

Looks for a free voice and assigns it to the given note. If a free voice is found, it marks it as busy with the note number and returns the voice index. If all voices are busy, it returns -1.

release_voice(note)

Looks through the busy_list for the provided note. If the note is found, frees the index and returns a Tuple with (True, index of found item). If the note is not found, returns (False, -1)

Prand

Random pattern that selects values randomly from a list.

Prand generates values by randomly selecting from a list with equal probability for each element. The same value can be selected consecutively.

Attributes:

Name	Type	Description
list		The list of values to select from randomly

Example

pattern = Prand([1, 2, 3, 4])
print(pattern.next())  # Random selection: 1, 2, 3, or 4
print(pattern.next())  # Another random selection

__init__(list)

Random pattern that selects values randomly from a list.

Prand generates values by randomly selecting from a list with equal probability for each element. The same value can be selected consecutively.

Attributes:

Name	Type	Description
list		The list of values to select from randomly

Example

pattern = Prand([1, 2, 3, 4])
print(pattern.next())  # Random selection: 1, 2, 3, or 4
print(pattern.next())  # Another random selection

next()

Get a random value from the list.

Returns:

Type	Description
Optional[float]	A randomly selected value from the list. Returns None
Optional[float]	if the list is empty.

Pseq

Sequential pattern that cycles through a list of values.

Pseq generates values by iterating through a list sequentially, wrapping back to the beginning when it reaches the end.

Attributes:

Name	Type	Description
list		The list of values to cycle through
index		Current position in the list (starts at -1)

Example

pattern = Pseq([1, 2, 3])
print(pattern.next())  # 1
print(pattern.next())  # 2
print(pattern.next())  # 3
print(pattern.next())  # 1 (cycles back)

__init__(list)

Sequential pattern that cycles through a list of values.

Pseq generates values by iterating through a list sequentially, wrapping back to the beginning when it reaches the end.

Attributes:

Name	Type	Description
list		The list of values to cycle through
index		Current position in the list (starts at -1)

Example

pattern = Pseq([1, 2, 3])
print(pattern.next())  # 1
print(pattern.next())  # 2
print(pattern.next())  # 3
print(pattern.next())  # 1 (cycles back)

go_back(n=1)

Move the sequence index back by n steps.

Parameters:

Name	Type	Description	Default
n		Number of steps to move back in the sequence	1

next()

Get the next value in the sequence.

Returns:

Type	Description
Optional[float]	The next value in the list, cycling back to the beginning
Optional[float]	when reaching the end. Returns None if the list is empty.

Pxrand

Exclusive random pattern that avoids immediate repetition.

Pxrand generates values by randomly selecting from a list while ensuring that the same value is never selected twice in a row. This is useful for creating varied sequences without consecutive duplicates.

Attributes:

Name	Type	Description
list		The list of values to select from
last_index		Index of the previously selected value

Note

This pattern requires a list with at least 2 elements to function properly and avoid repetition.

Example

pattern = Pxrand([1, 2, 3, 4])
print(pattern.next())  # Random selection: 1, 2, 3, or 4
print(pattern.next())  # Different from previous selection

__init__(list)

Exclusive random pattern that avoids immediate repetition.

Pxrand generates values by randomly selecting from a list while ensuring that the same value is never selected twice in a row. This is useful for creating varied sequences without consecutive duplicates.

Attributes:

Name	Type	Description
list		The list of values to select from
last_index		Index of the previously selected value

Note

This pattern requires a list with at least 2 elements to function properly and avoid repetition.

Example

pattern = Pxrand([1, 2, 3, 4])
print(pattern.next())  # Random selection: 1, 2, 3, or 4
print(pattern.next())  # Different from previous selection

next()

Get a random value that differs from the previous selection.

Returns:

Type	Description
Optional[float]	A randomly selected value from the list that is guaranteed
Optional[float]	to be different from the previous selection. Returns None
Optional[float]	if the list is empty.