./../../src/rthm-chain.lsp

## rthm-chain/add-voice [ Methods ]

[ Top ] [ rthm-chain ] [ Methods ]

DESCRIPTION

     Add a new voice to an existing rthm-chain object based on the rhythmic
     material and slot values already contained in that object.

     The main rthm-chain algorithm generates only two voices. Rather than
     generate further voices in the same fashion by which the first two were
     created, this method uses the already created rthm-seqs in the given
     rthm-chain object to create a new voice.

     The challenge here is that each rthm-seq potentially has its own time
     signature structure: There could be a 2/4 bar followed by 5/4 then 3/16,
     for example, or any other combination of any meter. So the method first
     analyses the time-signature structure of the existing rthm-seqs and saves
     those with the same bar/meter structure together in the order in which they
     occur. When creating the extra voice then, the method actually starts ahead
     of the main voice by choosing <offset> number of similar rthm-seqs in
     advance.

ARGUMENTS

     - A rthm-chain object.
     - The reference (key path) of the player within the given rthm-chain object
       whose rthm-seq-map is to serve as the 'parent voice', e.g. '(1 cl).
     - A symbol that will be the ID of the new player.

OPTIONAL ARGUMENTS

     - An integer that indicates an offset into the group of similar rthm-seq
       objects from which the new voice is to begin. (The generated voice will
       thus be ahead of the main voice). Default = 1.

RETURN VALUE

     Returns T.

EXAMPLE

    (let ((rch
           (make-rthm-chain
            'test-rch 150
            '((((e) e) ; 4 in total
               (- s (s) (s) s -)
               ({ 3 (te) - te te - })
               ((e.) s))
              (({ 3 (te) te (te) }) ; what we transition to
               ({ 3 - te (te) te - })
               ({ 3 (te) - te te - })
               ({ 3 (te) (te) te })))
            '((((q q) ; the 2/4 bars: 5 total
                ((q) q)
                ((q) q)
                ((q) (s) e.)
                (- e e - (e) e))
               (({ 3 te+te te+te te+te }) ; what we transition to
                (q - s e. -)
                (q (s) e.)
                (q (s) - s e -)
                ({ 3 te+te te+te - te te - })))
              ((((e.) s (e) e (s) e.) ; the 3/4 bars: 4 total
                (- e e - (e) e (q))
                (- e. s - - +e e - (q))
                (q (e.) s (q)))
               (({ 3 (te) (te) te+te te+te } (q)) ; what we transition to
                (- e. s - (q) (s) - s e -)
                ({ 3 te+te te } (q) q)
                ({ 3 - te te te - } (e) e { 3 (te) (te) te }))))
            :players '(fl cl))))
      (add-voice rch '(1 cl) 'ob))

SYNOPSIS

    (defmethod add-voice ((rc rthm-chain) parent new-player &optional (offset 1))

## rthm-chain/hash-least-used [ Functions ]

[ Top ] [ rthm-chain ] [ Functions ]

DESCRIPTION

     Return the least used key in a hash table. This may be used to retrieve the
     number of times the keys have been used as indices, for example.

ARGUMENTS

     - A hash table. This must be a lisp hash table object whose keys are all
       integers and whose values are all numbers.

OPTIONAL ARGUMENTS

     keyword arguments:
     - :start. The lowest key value we'll test. Default = 0.
     - :end. The highest key value we'll test. Default = number of items in the
       hash table.
     - :ignore. A list of keys to ignore when processing. NIL = process all
       keys. Default = NIL.
     - :auto-inc. T or NIL to determine whether the function will automatically
       increment the count of the returned key. T = automatically increment.
       Default = T.

RETURN VALUE

     The hash least used.

EXAMPLE

    (let ((h (make-hash-table)))
      (loop for i below 100 do
           (setf (gethash i h) 10000))
      (setf (gethash 10 h) 5
            (gethash 11 h) 4
            (gethash 12 h) 3
            (gethash 13 h) 2)
      (print (hash-least-used h :auto-inc nil))
      (print (hash-least-used h :auto-inc t))
      (print (hash-least-used h :auto-inc t))
      (print (hash-least-used h :auto-inc nil :start 12))
      (setf (gethash 2 h) 0)
      (print (hash-least-used h :auto-inc nil :start 3 :end 11))
      (print (hash-least-used h :auto-inc nil :end 11))
      (print (hash-least-used h :auto-inc nil :ignore '(2))))

    =>
    13
    13
    12
    13
    11
    2
    13

SYNOPSIS

    (defun hash-least-used (hash &key (start 0) end ignore (auto-inc t))

## rthm-chain/make-rthm-chain [ Functions ]

[ Top ] [ rthm-chain ] [ Functions ]

DESCRIPTION

     Create an instance of a rthm-chain object. The rthm-chain class enables the
     algorithmic generation of a rthm-seq-map (with just one section) and its
     associated rthm-seq-palette, which consists in turn of algorithmically
     generated rthm-seq objects.

     The rhythm-seq objects are made up of both faster material based on 1-beat
     groups and slower-moving counterpoint based on 2- or 3-beat groups.

     The rthm-chain class also allows for control of the degree of activity in
     the parts over time through user-specified envelopes.

     Rests are automatically inserted at regular but changing intervals.

     Specified 'sticking points' cause individual rhythms to be repeated a
     certain number of times. Sticking happens after rests and can also be
     controlled with an activity envelope.

     NB: Because this method uses the procession method internally, each
         collection of 1-beat-rthms and slower-rthms defined must contain at
         least four items.

     NB: Since this method automatically inserts rests into the chains, the user
         may like to implement the various tie-over-rests post-generation
         editing methods. If this is done, the handle-ties method may also be
         recommended, as the tie-over-rests methods only affect printed output
         and not MIDI output.

ARGUMENTS

     - A number, symbol, or string that is to be the ID of the new rthm-chain
       object.
     - An integer that is the number of beats to be generated prior to adding
       additional material created from sticking points and the automatic
       addition of rests.
     - A list with sublists of rhythms that are to be the 1-beat rhythms used to
       construct the faster-moving material of the rthm-seq-palette. Each
       sublist represents the repertoire of rhythms that will be used by the
       procession method. Each sublist must contain the same number of rthms but
       their number and the number of sublists is open. A transition will be
       made from one group of rhythms to the next over the whole output
       (i.e. not one unit to another within e.g. the 1-beat rhythms) according
       to a fibonacci-transition method.  NB Here and below, at least two lists
       are required: what we start with, and what we transition to.  If no
       transition is required you could of course just duplicate the rhythms via
       a let variable: (list rhythms rhythms).
     - A list with sublists of 2-beat and 3-beat full bars of rhythms used to
       construct the slower-moving counterpoint material of the
       rthm-seq-palette. This will be turned into a rthm-chain-slow object, and
       will therefore remain as lists of unparsed rhythms. Each sublist must
       contain the same number of rthms but their number and the number of
       sublists is open. A transition will be made from one group of rhythms to
       the next over the whole output (i.e. not one unit to another within
       e.g. the 1-beat rhythms) according to a fibonacci-transition method.
       NB: The rhythm units of slower-rthms must be expressed in single beats;
       e.g., a 2/4 bar must consist of q+q rather than h. The consolidate-notes
       method can be called afterwards if desired.

OPTIONAL ARGUMENTS

     keyword arguments:
     - :players. A list of two player IDs. When used in conjunction with a
       slippery-chicken object (which is the standard usage), these must be IDs
       as they are defined in that object's ENSEMBLE slot. The first player will
       play the 1-beat rhythms, the second the slower rhythms.
       Default = '(player1 player2).
     - :section-id. An integer that will be used as the ID of the rthm-seq-map
       created. NB: rthm-chain only creates rthm-seq-maps with one section,
       making it possible to create several different rthm-seq-map objects for
       different sections in the given piece, and requiring that these be
       manually assigned IDs. Additionally, any ID given here must match an
       existing ID within the other maps. Default = 1.
     - :activity-curve. A list of break-point pairs with y values from 1 to 10
       indicating the amount of activity there should be over the course of the
       piece. A value of 1 indicates that only 1 in 10 beats will have notes
       in/on them, and a value of 10 indicates that all beats will have
       notes. This process uses the patterns given in
       activity-levels::initialize-instance, where 1 means 'play' and 0 means
       'rest'. There are three templates for each level, so that if the curve
       remains on one level of activity for some time it won't always return the
       same pattern; these will be rotated instead. If the activity curve
       indicates a rest for one of the slower-rhythms groups, the whole 2-3 beat
       group is omitted. Default = '(0 10 100 10).
     - :do-rests. T or NIL to indicate whether to apply the automatic
       rest-insertion algorithm. T = use. Default = T.
     - :rests. A list of rhythmic duration units from which the durations will
       be drawn when using the automatic rest-insertion algorithm. The specified
       rests are used in a sequence determined by a recurring-event
       object. Default = '(e q q. w). NB: Each of these values must not resolve
       to less than one-quarter of the beat basis, either alone or in
       combination, as this could result in an attempt to create meters from
       fractional beats (e.g. 3.25). An error message will be printed in such
       cases.
     - :rest-cycle. A list of 2-item lists that indicate the pattern by which
       rests of specific rhythmic durations will be selected from the RESTS slot
       for automatic insertion. The first number of each pair is a 0-based
       position referring to the list of rests in the RESTS slot, and the second
       number is the number of times the rest at that particular position should
       be inserted. (This number does not mean that the selected rest will be
       inserted that many times at once, but rather that each consecutive time
       the rest algorithm selects one rest to be inserted, it will insert that
       specific rest, for the specified number of consecutive times.) For
       example, (0 3) indicates that for the next three times that the rest
       algorithm selects one rest to insert, it will select the rest located at
       position 0 in the list of rests in the RESTS slot (e by default).
       Default ='((0 3) (1 1) (0 2) (2 1) (1 1) (3 1)).
     - :rest-re. A list of 2-item lists that indicate the pattern by which rests
       will be automatically inserted. The first number of each pair determines
       how many events occur before inserting a rest, and the second number of
       each pair determines how many times that period will be repeated. For
       example, (2 3) indicates that a rest will be inserted every two events,
       three times in a row. The list passed here will be treated as data for a
       recurring-event object that will be repeatedly cycled through.
       Default = '((2 3) (3 2) (2 2) (5 1) (3 3) (8 1)).
     - :do-rests-curve. A list of break-point pairs with y values of either 0 or
       1 indicating whether the do-rests algorithm is active or disabled. These
       values are interpolated between each pair, with all values 0.5 and higher
       being rounded up to 1 and all below 0.5 rounded to 0. Default = NIL.
     - :do-sticking. T or NIL to indicate whether the method should apply the
       sticking algorithm. T = apply. Default = T.
     - :sticking-rthms. A list of rhythmic units that will serve as the rhythms
       employed by the sticking algorithm. These are generated at initialization
       if not specified here. NB: This list is used to create a list using the
       procession algorithm at initialization, so it is best to apply something
       similar to the default if not accepting the default. If a circular-sclist
       object is provided here, it will be used instead of the default
       procession. Default = '(e e e. q e s).
     - :sticking-repeats. A list of integers to indicate the number of
       repetitions applied in sticking segments. When the values of this list
       have been exhausted, the method cycles to the beginning and continues
       drawing from the head of the list again. NB: This list is made into a
       circular-sclist object when the given rthm-chain object is initialized
       unless a circular-sclist object is explicitly provided.
       Default = '(3 5 3 5 8 13 21).
     - :sticking-curve. A list of break-point pairs that acts as an activity
       envelope to control the sticking, which always occurs after rests. As
       with the activity curve, this curve can take y values up to 10, but also
       allows 0. A y value of 0 or 1 here refers to either a specific number of
       repeats (1) or none (0). The number of repeats may be determined, for
       example, by use of the procession method, such as
       (procession 34 '(2 3 5 8 13) :peak 1 :expt 3). Every sticking point is
       accompanied by a slower group, which is simply chosen in sequence and
       repeated for the duration of the sticking period.
       Default = '(0 2 100 2).
     - :do-sticking-curve. A list of break-point pairs that can be used,
       alternatively, to control whether the sticking algorithm is being applied
       or not at any given point over the course of the piece. The y values for
       this curve should be between 0 and 1, and the decimal fractions achieved
       from interpolation will be rounded. The 1 values resulting from this
       curve will only be actively applied to if do-sticking is set to T.
       Default = NIL.
     - :harmonic-rthm-curve. A list of break-point pairs that indicates how many
       slower-rthms will be combined into one rthm-seq (each rthm-seq has a
       single harmony). The default is 2 bars (slower-rthms) per rthm-seq,
       i.e. '(0 2 100 2).
     - :split-data. NIL or a two-item list of integers that are the minimum and
       maximum beat duration of bars generated. If NIL, the bars will not be
       split. These values are targets only; the method may create bars of
       different lengths if the data generated cannot be otherwise split.
       NB: The values given here will apply to a different beat basis depending
       on time signature of each individual bar, rather than on a consistent
       beat basis, such as quarters or eighths. Since this method produces bars
       of different lengths with time signatures of differing beat bases
       (e.g. 16, 8, 4 etc.) before it applies the split algorithm, a minimum
       value of 4, for example, can result in bars of 4/16, 4/8, 4/4 etc.
       Default = '(2 5)
     - :1-beat-fibonacci. T or NIL to indicate whether the sequence of 1-beat
       rhythms is to be generated using the fibonacci-transitions method or the
       processions method. T = use fibonacci-transitions method. Default = NIL.
     - :slow-fibonacci. T or NIL to indicate whether the sequence of the slow
       rhythms will be generated using the fibonacci-transitions method or the
       processions method. This affects the order in which each 2- or 3-beat
       unit is used when necessary, not the order in which each 2- or 3-beat
       unit is selected; the latter is decided by the next element in the DATA
       slot of the rthm-chain-slow object, which simply cycles through
       '(2 3 2 2 3 2 2 3 3 3). T = use fibonacci-transitions method.
       Default = NIL.

RETURN VALUE

     A rthm-chain object.

EXAMPLE

    ;; An example using a number of the keyword arguments.
    (make-rthm-chain
     'test-rch 23
     '((((e) e) ; 4 in total
        (- s (s) (s) s -)
        ({ 3 (te) - te te - })
        ((e.) s))
       (({ 3 (te) te (te) }) ; what we transition to
        ({ 3 - te (te) te - })
        ({ 3 (te) - te te - })
        ({ 3 (te) (te) te })))
     '((((q q) ; the 2/4 bars: 5 total
         ((q) q)
         ((q) q)
         ((q) (s) e.)
         (- e e - (e) e))
        (({ 3 te+te te+te te+te }) ; what we transition to
         (q - s e. -)
         (q (s) e.)
         (q (s) - s e -)
         ({ 3 te+te te+te - te te - })))
       ((((e.) s (e) e (s) e.) ; the 3/4 bars: 4 total
         (- e e - (e) e (q))
         (- e. s - - +e e - (q))
         (q (e.) s (q)))
        (({ 3 (te) (te) te+te te+te } (q)) ; what we transition to
         (- e. s - (q) (s) - s e -)
         ({ 3 te+te te } (q) q)
         ({ 3 - te te te - } (e) e { 3 (te) (te) te }))))
     :players '(fl cl)
     :slow-fibonacci t
     :activity-curve '(0 1 100 10)
     :harmonic-rthm-curve '(0 1 100 3)
     :do-sticking t
     :do-sticking-curve '(0 1 25 0 50 1 75 0 100 1)
     :sticking-curve '(0 0 100 10)
     :sticking-repeats '(3 5 7 11 2 7 5 3 13)
     :sticking-rthms '(e s. 32 e.)
     :split-data '(4 7))

    =>
    RTHM-CHAIN: 1-beat-rthms: (((E E) (S S S S) (TE TE TE) (E. S))
                               ((TE TE TE) (TE TE TE) (TE TE TE) (TE TE TE)))
                slower-rthms: ((((Q Q) ((Q) Q) ((Q) Q) ((Q) (S) E.)
                                 (- E E - (E) E))
                                (({ 3 TE+TE TE+TE TE+TE }) (Q - S E. -) (Q (S) E.)
                                 (Q (S) - S E -) ({ 3 TE+TE TE+TE - TE TE - })))
                               ((((E.) S (E) E (S) E.) (- E E - (E) E (Q))
                                 (- E. S - - +E E - (Q)) (Q (E.) S (Q)))
                                (({ 3 (TE) (TE) TE+TE TE+TE } (Q))
                                 (- E. S - (Q) (S) - S E -) ({ 3 TE+TE TE } (Q) Q)
                                 ({ 3 - TE TE TE - } (E) E { 3 (TE) (TE) TE }))))
                1-beat-fibonacci: NIL
                num-beats: 23
                slow-fibonacci: T
                num-1-beat-rthms: 4
                num-1-beat-groups: 2
                sticking-curve: (0.0 0 22 10)
                harmonic-rthm-curve: (0.0 1 22 3)
                beat: 4
                do-sticking: T
                do-rests: T
                do-sticking-curve: (0.0 1 5.5 0 11.0 1 16.5 0 22 1)
                do-rests-curve: NIL
                sticking-al: (not printed for brevity's sake)
                sticking-rthms: (E S. E S. 32 E 32 E E E. S. 32 S. E. S. 32 S. 32
                                 E. E)
                sticking-repeats: (3 5 3 5 7 3 7 3 3 11 5 7 5 11 5 7 5 7 11 3 7 3 3
                                   11 5 7 5 11 3 7 3 7 11 5 7 5 5 11 3 11 3 2 11 2
                                   11 2 7 2 7 2 2 5 5 3 5)
                activity-curve: (0.0 1 22 10)
                main-al: (not printed for brevity's sake)
                slower-al: (not printed for brevity's sake)
                num-slower-bars: 22
                rcs: (not printed for brevity's sake)
                rests: (E Q Q. W)
                rest-re: (not printed for brevity's sake)
                rest-cycle: ((0 3) (1 1) (0 2) (2 1) (1 1) (3 1))
                num-rthm-seqs: 19
                section-id: 1
                split-data: (4 7)
    RTHM-SEQ-MAP: num-players: 2
                  players: (FL CL)
    SC-MAP: palette id: RTHM-CHAIN-RSP
    [...]

SYNOPSIS

    (defun make-rthm-chain (id num-beats 1-beat-rthms slower-rthms &key
                            (1-beat-fibonacci nil)
                            (slow-fibonacci nil)
                            (players '(player1 player2))
                            (section-id 1)
                            (rests '(e q q. w))
                            (do-rests t)
                            (do-rests-curve nil)
                            (rest-re '((2 3) (3 2) (2 2) (5 1) (3 3) (8 1)))
                            (rest-cycle '((0 3) (1 1) (0 2) (2 1) (1 1) (3 1)))
                            (activity-curve '(0 10 100 10))
                            (sticking-curve '(0 2 100 2))
                            (harmonic-rthm-curve '(0 2 100 2))
                            (do-sticking t)
                            (do-sticking-curve nil)
                            (sticking-repeats '(3 5 3 5 8 13 21))
                            (sticking-rthms '(e e e. q e s))
                            (split-data '(2 5)))

## rthm-chain/procession [ Functions ]

[ Top ] [ rthm-chain ] [ Functions ]

DATE

     26-Jan-2010

DESCRIPTION

     Generate a list of a specified length consisting of items extrapolated from
     a specified starting list. All elements of the resulting list will be
     members of the original list.

     The method generates the new list by starting with the first 3 elements of
     the initial list and successively adding consecutive elements from the
     initial list until all elements have been added.

ARGUMENTS

     - An integer that is the number of items in the list to be generated.
     - A list of at least 4 starting items or an integer >=4. If an integer is
       given rather than a list, the method will process a list of consecutive
       numbers from 1 to the specified integer.

OPTIONAL ARGUMENTS

     keyword arguments:
     - :peak. A decimal number >0.0 and <=1.0. This number indicates the target
       location in the new list at which the last element is to finally occur,
       whereby e.g. 0.7 = ~70% of the way through the resulting list. This is an
       approximate value only. The last element may occur earlier or later
       depending on the values of the other arguments. In particular, initial
       lists with a low number of items are likely to result in new lists in
       which the final element occurs quite early on, perhaps even nowhere near
       the specified peak value. Default = 0.7.
     - :expt. An exponent (floating point number) to indicate the "curve" that
       determines the intervals at which each successive element of the initial
       list is introduced to the new list. A higher number indicates a steeper
       exponential curve. Default = 1.3.
     - :orders. The patterns by which the elements are added. The method
       cyclically applies these orders, the numbers 1, 2, and 3 representing the
       three least used elements at each pass. These orders must therefore
       contain all of the numbers 1, 2, and 3, and those numbers only.
       Default = '((1 2 1 2 3) (1 2 1 1 3) (1 2 1 3)).

RETURN VALUE

     Returns two values, the first being the new list, with a secondary value
     that is a list of 2-item lists that show the distribution of each element
     in the new list.

EXAMPLE

    (procession 300 30 :peak 0.1)

    =>
    (1 2 1 2 3 4 5 4 4 6 7 8 7 9 10 11 10 11 12 13 14 13 13 15 16 17 16 18 19 20 19
       20 21 22 23 22 22 24 25 26 25 27 28 29 28 29 30 3 5 3 3 6 8 9 8 12 14 15 14
       15 17 18 21 18 18 23 24 26 24 27 1 2 1 2 30 5 6 5 5 7 9 10 9 11 12 16 12 16
       17 19 20 19 19 21 23 25 23 26 27 28 27 28 29 4 6 4 4 30 7 8 7 10 11 13 11 13
       14 15 17 15 15 20 21 22 21 24 25 26 25 26 29 1 2 1 1 30 3 6 3 8 9 10 9 10 12
       14 16 14 14 17 18 20 18 22 23 24 23 24 27 28 29 28 28 30 2 5 2 6 7 8 7 8 11
       12 13 12 12 16 17 19 17 20 21 22 21 22 25 26 27 26 26 29 3 4 3 30 5 6 5 6 9
       10 11 10 10 13 15 16 15 18 19 20 19 20 23 24 25 24 24 27 1 29 1 30 2 4 2 4 7
       8 9 8 8 11 13 14 13 16 17 18 17 18 21 22 23 22 22 25 27 28 27 29 3 5 3 5 30
       6 7 6 6 9 11 12 11 14 15 16 15 16 19 20 21 20 20 23 25 26 25 28 1 29 1 29 30
       2 4 2 2 7 9 10 9 12 13 14 13 14 17 18), ((2 12) (20 11) (14 11) (13 11)
       (9 11) (6 11) (1 11) (29 10) (25 10) (22 10) (18 10) (17 10) (16 10) (15 10)
       (12 10) (11 10) (10 10) (8 10) (7 10) (5 10) (4 10) (3 10) (30 9) (28 9)
       (27 9) (26 9) (24 9) (23 9) (21 9) (19 9))

    (procession 300 30 :peak 0.9)

    =>
    (1 2 1 2 3 1 3 1 1 4 2 3 2 4 3 4 3 4 5 2 4 2 2 5 1 3 1 5 3 4 3 4 5 1 5 1 1 6 2
       5 2 6 4 5 4 5 6 3 6 3 3 7 5 6 5 7 2 6 2 6 7 6 7 6 6 8 4 7 4 8 7 8 7 8 9 7 8
       7 7 9 8 9 8 10 8 9 8 9 10 8 9 8 8 10 9 10 9 11 9 10 9 10 11 10 11 10 10 12
       10 11 10 12 11 12 11 12 13 11 12 11 11 13 12 13 12 14 12 13 12 13 14 13 14
       13 13 15 13 14 13 15 11 14 11 14 15 14 15 14 14 16 15 16 15 17 15 16 15 16
       17 16 17 16 16 18 16 17 16 18 17 18 17 18 19 17 18 17 17 19 18 19 18 20 18
       19 18 19 20 19 20 19 19 21 15 20 15 21 20 21 20 21 22 20 21 20 20 22 21 22
       21 23 21 22 21 22 23 22 23 22 22 24 23 24 23 25 23 24 23 24 25 24 25 24 24
       26 23 25 23 26 25 26 25 26 27 26 27 26 26 28 25 27 25 28 27 28 27 28 29 27
       28 27 27 29 28 29 28 30 24 29 24 29 30 26 29 26 26 30 28 29 28 30 19 29 19
       29 30 22 25 22 22 30 12 27 12 30 14 16 14 16 30 17), ((8 12) (22 11)
       (16 11) (14 11) (12 11) (11 11) (10 11) (4 11) (3 11) (2 11) (26 10)
       (19 10) (17 10) (15 10) (13 10) (9 10) (7 10) (6 10) (5 10) (1 10)
       (29 9) (28 9) (27 9) (25 9) (24 9) (23 9) (21 9) (20 9) (18 9) (30 8))

SYNOPSIS

    (defun procession (num-results items
                       &key
                       ;; what proportion of the way through should we aim to reach
                       ;; the max number of items?  NB This is approximate only:
                       ;; you may find the first occurrence of the highest element
                       ;; earlier or later depending on the values of the other
                       ;; arguments.  In particular, with a low number of items the
                       ;; highest element will be hit very early on, perhaps
                       ;; nowhere near the peak argument.
                       (peak 0.7)
                       ;; for an exponential curve going from 3 to num <items>
                       (expt 1.3)
                       ;; these are the orders we'll use at the beginning
                       ;; (cyclically). They will then be used when we've gone
                       ;; beyond 3 items by always using the 3 least used items.
                       ;; NB This must contain the numbers 1, 2, and 3 only but
                       ;; there can be 1 or any number of sublists.
                       (orders '((1 2 1 2 3) (1 2 1 1 3) (1 2 1 3))))

## rthm-chain/reset [ Methods ]

[ Top ] [ rthm-chain ] [ Methods ]

DESCRIPTION

     Reset the various circular-sclist objects within the given rthm-chain
     object to their initial state.

ARGUMENTS

     - A rthm-chain object.

OPTIONAL ARGUMENTS

     (- :where. This argument is ignored by the method as it is only present due
        to inheritance.)

RETURN VALUE

     Returns T.

EXAMPLE

    ;;; Print the results of applying get-next to the STICKING-RTHMS slot of the
    ;;; given rthm-chain object, repeat, reset, and print again to see that the
    ;;; get-next now begins at the beginning of the slot again.

    (let ((rch
           (make-rthm-chain
            'test-rch 150
            '((((e) e) ; 4 in total
               (- s (s) (s) s -)
               ({ 3 (te) - te te - })
               ((e.) s))
              (({ 3 (te) te (te) }) ; what we transition to
               ({ 3 - te (te) te - })
               ({ 3 (te) - te te - })
               ({ 3 (te) (te) te })))
            '((((q q) ; the 2/4 bars: 5 total
                ((q) q)
                ((q) q)
                ((q) (s) e.)
                (- e e - (e) e))
               (({ 3 te+te te+te te+te }) ; what we transition to
                (q - s e. -)
                (q (s) e.)
                (q (s) - s e -)
                ({ 3 te+te te+te - te te - })))
              ((((e.) s (e) e (s) e.) ; the 3/4 bars: 4 total
                (- e e - (e) e (q))
                (- e. s - - +e e - (q))
                (q (e.) s (q)))
               (({ 3 (te) (te) te+te te+te } (q)) ; what we transition to
                (- e. s - (q) (s) - s e -)
                ({ 3 te+te te } (q) q)
                ({ 3 - te te te - } (e) e { 3 (te) (te) te })))))))
      (print
       (loop repeat 19
          collect (data (get-next (sticking-rthms rch)))))
      (print
       (loop repeat 19
          collect (data (get-next (sticking-rthms rch)))))
      (reset rch)
      (print
       (loop repeat 19
          collect (data (get-next (sticking-rthms rch))))))

    =>
    (E E E E E. E E. E E Q E E. E Q E. Q E. Q E)
    (E E E E E E. E E. E E Q E E. E Q E. Q E. Q)
    (E E E E E. E E. E E Q E E. E Q E. Q E. Q E)

SYNOPSIS

    (defmethod reset ((rc rthm-chain) &optional ignore1 ignore2)

## rthm-chain/rthm-chain-gen [ Methods ]

[ Top ] [ rthm-chain ] [ Methods ]

DESCRIPTION

     Generate a chain of rhythms using the procession function (internally).

     The basic algorithm for generating a rthm-chain object of two parts is as
     follows: The user provides an arbitrary number of 1-beat rthms (e.g. s s
     (e)) and 2-3 beat slower-moving counterpoints. The method generates a
     sequence from these using the procession function. Next the activity curve
     is applied to this, and after that the insertion of rests. Then the
     'sticking points' are generated: These come after the rests, and the
     activity curves applied to these count inserted rests not seqs or beats.

     NB: Rests are put into the given rthm-seq object mid-sequence, so sticking
         points won't come directly after the rests, rather, at the end of the
         seq.

     The activity curves that turn notes into rests will be queried every beat,
     so if an activity level is changed, the method won't wait until the end of
     the previous level's ten beats.

     NB: This method is not generally called by the user (though it can be of
         course); rather, it's called by the init function.

ARGUMENTS

     - A rthm-chain object.

OPTIONAL ARGUMENTS

     keyword arguments:
     - :rests. T or NIL to indicate whether rests are to be automatically
       inserted. T = automatically insert. Default = T.
     - :stick. T or NIL to indicate whether to generate the sticking points. T =
       generate sticking points. Default = T.
     - :num-beats. NIL or an integer to indicate how many beats are to be used
       for the algorithm. NB: The method will generate considerably more beats
       if also generating sticking points and inserting rests; this number
       merely refers to the number of standard 1-beat rhythms to be generated.
       If NIL, the method will obtain the number of beats from the NUM-BEATS
       slot of the rthm-chain instance. Default = NIL.
     - :use-fibonacci. T or NIL to indicate whether to use the
       fibonacci-transitions method when generating the sequence from the 1-beat
       rhythms (in which case these will be repeated) or the procession
       algorithm (in which case they'll be alternated). T = use the
       fibonacci-transitions method. Default = T.
     - :section-id. An integer that is the section ID of the rthm-chain object
       to be generated. This will determine the section of the rthm-seq-map into
       which the references will be placed. The rthm-seq objects themselves will
       also be parcelled up into an object with this ID, so ID conflicts can be
       avoided if combining two or more sections generated by separate
       rthm-chain objects. Default = 1.
     - :wrap. An integer or NIL to determine the position within the list of
       1-beat rhythms and slow rhythms from which the generated rhythm chain
       will begin. NIL = begin at the beginning. Default = NIL.
     - :split. T or NIL to indicate whether to split up longer generated bars
       (e.g. 7/4) into smaller bars. If this is a two-element list it represents
       the min/max number of beats in a bar (where a 6/8 bar is two compound
       beats). Default = '(2 5).

RETURN VALUE

     the number of rthm-seqs we've generated

SYNOPSIS

    (defmethod rthm-chain-gen ((rc rthm-chain)
                               &key
                               (use-fibonacci t)
                               (rests t)
                               (stick t)
                               (section-id 1)
                               num-beats
                               wrap)

## rthm-chain/split [ Methods ]

[ Top ] [ rthm-chain ] [ Methods ]

DATE

     29-Jan-2011

DESCRIPTION

     Split the longer generated bars into smaller ones where possible.

ARGUMENTS

     - A rthm-chain object.

OPTIONAL ARGUMENTS

     keyword arguments:
     - :min-beats. An integer that is the minimum number of beats in the
       resulting bars. This is a target-length only, and may not be adhered to
       strictly if durations do not allow. Default = 2.
     - :max-beats. An integer that is the maximum number of beats in the
       resulting bars. This is a target-length only, and may not be adhered to
       strictly if durations do not allow. Default = 5.
     - :warn. T or NIL to indicate whether to print a warning to the listener if
       the current bar cannot be split. T = print. Default = NIL.
     - :clone. T or NIL to indicate whether the rthm-seq of the given rthm-chain
       object should be changed in place or changes should be made to a copy of
       that object. T = create a copy to be changed. Default = T.

RETURN VALUE

     Returns T.

EXAMPLE

    ;;; Make a rthm-chain object using make-rthm-chain with the :split-data
    ;;; argument set to NIL and print the number of bars in each resulting rthm-seq
    ;;; object. Apply the split method and print the number of bars again to see
    ;;; the change.

    (let* ((rch
            (make-rthm-chain
             'test-rch 150
             '((((e) e) ; 4 in total
                (- s (s) (s) s -)
                ({ 3 (te) - te te - })
                ((e.) s))
               (({ 3 (te) te (te) }) ; what we transition to
                ({ 3 - te (te) te - })
                ({ 3 (te) - te te - })
                ({ 3 (te) (te) te })))
             '((((q q) ; the 2/4 bars: 5 total
                 ((q) q)
                 ((q) q)
                 ((q) (s) e.)
                 (- e e - (e) e))
                (({ 3 te+te te+te te+te }) ; what we transition to
                 (q - s e. -)
                 (q (s) e.)
                 (q (s) - s e -)
                 ({ 3 te+te te+te - te te - })))
               ((((e.) s (e) e (s) e.) ; the 3/4 bars: 4 total
                 (- e e - (e) e (q))
                 (- e. s - - +e e - (q))
                 (q (e.) s (q)))
                (({ 3 (te) (te) te+te te+te } (q)) ; what we transition to
                 (- e. s - (q) (s) - s e -)
                 ({ 3 te+te te } (q) q)
                 ({ 3 - te te te - } (e) e { 3 (te) (te) te }))))
             :split-data nil)))
      (print
       (loop for rs in (data (get-data-data 1 (palette rch)))
          collect (num-bars rs)))
      (split rch :min-beats 1 :max-beats 3 :clone nil)
      (print
       (loop for rs in (data (get-data-data 1 (palette rch)))
          collect (num-bars rs))))

    =>
    (1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2
     2 2 2 2 2 2 2 1 1 2 2 1 1 2 2 2 2 1 1 2 2 2 2 2 2 2 2 1 1 2 2 2 2 2 2 2 2
     2 2)
    (1 1 4 4 2 7 4 4 3 3 4 4 2 9 7 7 2 5 5 5 2 6 1 1 2 13 3 3 4 4 5 5 2 7 5 5
     7 7 9 9 2 7 2 9 3 3 2 9 1 1 5 5 9 9 3 3 2 7 5 5 4 4 2 11 1 1 2 10 2 9 2 6
     7 7 7 7)

SYNOPSIS

    (defmethod split ((rc rthm-chain) &key
                      (min-beats 2) (max-beats 5) warn (clone t))

## rthm-seq-map/rthm-chain [ Classes ]

[ Top ] [ rthm-seq-map ] [ Classes ]

NAME

     rthm-chain

     File:             rthm-chain.lsp

     Class Hierarchy:  named-object -> linked-named-object -> sclist ->
                       circular-sclist -> assoc-list -> recursive-assoc-list ->
                       sc-map -> rthm-seq-map -> rthm-chain

     Version:          1.0.3

     Project:          slippery chicken (algorithmic composition)

     Purpose:          Algorithmic generation of rthm-seqs that include
                       slower-moving counterpoint and a means to control
                       activity development through curves.  Here we generate a
                       rthm-seq-map and its associated palette algorithmically.

                       Say we have 9 irregular 1 beat duration patterns; these
                       would enter in the sequence defined by (procession x 9)
                       where x would be the number of patterns to generate.

                       Rests are inserted at regular but changing intervals e.g

                       3x every 2 beats (6)
                       2x every 3 beats (6)
                       3x every 5 beats (15)
                       2x every 8 beats (16)

                       e, q, and q. rests are used by default, in a sequence
                       determined by a recurring-event instance.

                       In order to make music that 'progresses' we have curves
                       with y values from 1-10 indicating how much activity
                       there should be: 1 would mean only 1 in 10 beats would
                       have notes in/on them, 10 would indicate that all do.  We
                       use the patterns given in
                       activity-levels::initialize-instance, where 1 means
                       'play', 0 means 'rest'.  There are three examples of each
                       level so that if we stick on one level of activity for
                       some time we won't always get the same pattern: these
                       will instead be cycled through.

                       A slower moving (bass) line is also added that is made up
                       of 2 or 3 beat groups---if the activity curve indicates a
                       rest, then the whole 2-3 beat group is omitted.

                       There are also 'sticking points' where a rhythm will be
                       repeated a certain number of times (either s, e, e., or q
                       by default).  Sticking happens after rests.  This can be
                       controlled with an activity envelope too, also indicating
                       one of the 10 patterns above (but also including 0).  A 0
                       or 1 unit here would refer to a certain number of repeats
                       (1) or none (0).  How many repeats could be determined by
                       something like: (procession 34 '(2 3 5 8 13) :peak 1
                       :expt 3) There's always a slower group to accompany the
                       sticking points: simply the next in the sequence,
                       repeated for as long as we stick

                       The harmonic-rthm curve specifies how many slower-rthms
                       will be combined into a rthm-seq (each rthm-seq has a
                       single harmony).  The default is 2 bars (slower-rthms)
                       per rthm-seq.

     Author:           Michael Edwards: m@michael-edwards.org

     Creation date:    4th February 2010

     $$ Last modified: 18:13:10 Sat Jun  8 2013 BST

     SVN ID: $Id: rthm-chain.lsp 3940 2013-06-19 10:04:04Z medward2 $