NAME
Music::Duration::Partition - Partition a musical duration into rhythmic phrases
VERSION
version 0.0600
SYNOPSIS
use MIDI::Simple;
use Music::Duration::Partition;
use Music::Scales;
my $mdp = Music::Duration::Partition->new(
size => 8, # 2 measures in 4/4 time
pool => [qw(hn dqn qn en)],
);
$mdp->pool_select(sub { ... }); # Optional
my $motif = $mdp->motif;
my @scale = get_scale_MIDI('C', 4, 'major');
my $score = MIDI::Simple->new_score;
for my $n (0 .. 31) { # 4 loops over the motif
$score->n($motif->[$n % @$motif], $scale[int rand @scale]);
}
$score->write_score('motif.mid');
# The pool may also be made of MIDI durations
$mdp = Music::Duration::Partition->new(
size => 100,
pool => [qw(d50 d25)],
weights => [0.7, 0.3], # Optional
);
# The pool may also be grouped
$mdp = Music::Duration::Partition->new(
size => 4,
pool => [qw(hn qn tqn)],
groups => [0, 0, 3], # Optional
);DESCRIPTION
A Music::Duration::Partition divides a musical duration given by size, into rhythmic phrases of smaller durations drawn from the pool.
For example, to generate a measure in 5/4 time, set size equal to 5 and set the pool to an array-reference of MIDI::Simple durations whose lengths are less than or equal to 5 quarter notes.
To generate a measure in 5/8 time, set size equal to 2.5 (meaning 5 eighth notes).
ATTRIBUTES
durations
$durations = $mdp->durations;A hash reference of duration lengths (keyed by duration name).
Default: \%MIDI::Simple::Length
size
$size = $mdp->size;The value, in quarter notes, of the duration to partition.
Default: 4
pool
$pool = $mdp->pool;The list of possible note durations to use in constructing a rhythmic motif.
Default: [ keys %MIDI::Simple::Length ] (wn, hn, qn, ...)
This can be either a list of duration names, as in the example, or duration values, specified with a preceding 'd'. A mixture of both is not well defined. YMMV
pool_select
$code = $mdp->pool_select->();
$mdp->pool_select( sub { ... } );A code reference used to select an item from the given duration pool.
Default: Random item from pool
weights
$weights = $mdp->weights;Specification of the frequency of pool item selection.
The number of weights must equal the number of pool entries. The weights do not have to sum to 1 and can be any relative numbers.
Default: Equal probability for each pool entry
groups
$groups = $mdp->groups;An array reference of entries that represent the number of times that a pool item is selected in sequence.
The number of groups must equal the number of pool entries.
Default: Zero for each pool entry
* Zero and one mean the same thing for grouping. So if needed, an entry should have a value greater than one.
pool_group
$pool_group = $mdp->pool_group;A hash reference of pool keys and group values, respectively.
This attribute is computed and any setting given in the constructor is ignored.
verbose
$verbose = $mdp->verbose;Show the progress of the motif method.
Default: 0
METHODS
new
$mdp = Music::Duration::Partition->new(%arguments);Create a new Music::Duration::Partition object.
motif
$motif = $mdp->motif;Generate a rhythmic phrase of the given size.
This method returns a possibly different rhythmic motif each time it is called.
The default pool_select used constructs this by selecting a pool duration at random, that fits into the size remaining after each application, in a loop until the size is met.
SEE ALSO
The eg/* and t/01-methods.t programs in this distribution.
AUTHOR
Gene Boggs <gene@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2020 by Gene Boggs.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.