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• By opmo
– Update:
SNIPPET – length snippet will display without a line staff.

To display the length SNIPPET line staff, set the *SNIPPET-LENGTH-LINE* to T.
(defparameter *snippet-length-line* T "Enable or disable the length snippet line staff display.") The default is: NIL

– Fixes:
Bug fix found in length conversion to length-symbols function.
Missing OM Developer documents (English version).

Best wishes,
Janusz
• By opmo
– Function name changes:
LENGTH-DIVIDE2 to LENGTH-SUBDIVISION
LENGTH-DIVIDE3 to LENGTH-SYNCOPATE

– Function update:
LENGTH-DIVIDE – changes to arguments.
LENGTH-SUBDIVISION – changes to arguments.
LENGTH-SYNCOPATE – changes to arguments.
POLYGON-RHYTHM – enable fixed sides polygon.

– Note:
If you used any of the functions:
LENGTH-DIVIDE, LENGTH-DIVIDE2 or LENGTH-DIVIDE3 in your scores,
please check new documents in order to make the necessary correction.

– New:
Enable or disable the DO-VERBOSE macro.
(defparameter *do-verbose* nil "Enable or disable traces printed by do-verbose.")

length-divide
This function is able to divide number of lengths to a given division value. The :set and :ignore option increases the control for the desired result. When processing the omn-form sequence an optional third value allows you to fill intervalic steps (a root transposition) to new length values derived from the divisions.

(setf rhy '(1/4 1/4 1/4 1/4)) (length-divide '(2 2) rhy) => (1/8 1/8 1/4 1/4 1/8 1/8) (length-divide '(2 4) rhy) => (1/4 1/16 1/16 1/16 1/16 1/16 1/16 1/16 1/16 1/4)
Example:
(length-divide '(1 2) '(1/4 -1/8 1/16 1/16 -1/32 -3/32 1/8 1/1) :seed 34) => (1/4 -1/8 1/16 1/32 1/32 -1/32 -3/32 1/8 1)
In the example above only 1 length is divided by 2 - that is the 1/16. In the example below 4 lengths are divided by 2.
(length-divide '(4 2) '(1/4 -1/8 1/16 1/16 -1/32 -3/32 1/8 1/1) :seed 34) => (1/8 1/8 -1/8 1/16 1/32 1/32 -1/32 -3/32 1/16 1/16 1/2 1/2) (length-divide '(1 2) '(1/4 -1/8 1/16 1/16 -1/32 -3/32 1/8 1/1) :set 'min :seed 34) => (1/4 -1/8 1/32 1/32 1/16 -1/32 -3/32 1/8 1) (length-divide '(1 4) '(1/4 -1/8 1/16 1/16 -1/32 -3/32 1/8 1/1) :set 1/8 :seed 34) => (1/4 -1/8 1/16 1/16 -1/32 -3/32 1/32 1/32 1/32 1/32 1) (length-divide '((2 3) (1 2)) '((1/4 -1/8 1/16 1/16) (1/32 -3/32 1/8 1/1)) :ignore 'max :seed 45) => ((1/4 -1/8 1/48 1/48 1/48 1/48 1/48 1/48) (1/64 1/64 -3/32 1/8 1)) (length-divide '((2 4) (1 2)) '((q -e s s) (s -e. e w)) :set 'max :ignore 1 :seed 65) => ((1/16 1/16 1/16 1/16 -1/8 1/16 1/64 1/64 1/64 1/64) (1/16 -3/16 1/16 1/16 1))
OMN:
(setf mat1 '(q c4 d4 e4 f4 g4 a4 b4)) (length-divide '(3 4) mat1 :seed 45) => (s d4 bb3 cs4 b3 cs4 eb4 c4 e4 q s g4 e4 eb4 fs4 q g4 a4 b4)
Symbol 'r will apply repeat function:
(length-divide '(3 4 r) mat1 :seed 45) => (s c4 c4 c4 c4 d4 d4 d4 d4 q e4 s f4 f4 f4 f4 q g4 a4 b4)
Here we use a set of interval values at the end of the division list:
(length-divide '(3 4 (13 0 1 13)) mat1 :seed 45) => (s cs5 c4 cs4 cs5 eb5 d4 eb4 eb5 q e4 s fs5 f4 fs4 fs5 q g4 a4 b4) (setf mat2 '((e c4 p e4 mp g4 he c5 p) (q c4 f c4 cs4 mp - d5 p d5) (q cs5 mf = - - cs5 p =))) (length-divide '((1 4) (2 4) (2 5)) mat2 :seed 34) => ((e c4 p e4 mp t a4 f4 gs4 fs4 he c5 p) (q c4 f s b3 cs4 bb3 d4 q cs4 mp - d5 p s c5 e5 cs5 eb5) (q cs5 mf cs5 - - 5q eb5 p b4 c5 d5 eb5 c5 eb5 b4 d5 c5))
In the example below we assign three series of division values to variables s1, s2 and s3:
(setf s1 '(3 4 (6 12 18 24)) s2 '(3 4 ((13 1 13 0) (13 0 7 1) r)) s3 '(2 5 ((13 0 13 0 13) ?)) ) (length-divide (list s1 s2 s3) mat2 :seed 34) => ((e c4 p t bb4 mp e5 bb5 e6 cs5 g5 cs6 g6 et fs5 p c6 fs6 c7) (q c4 f s cs5 cs4 cs5 c4 q cs4 mp - s eb6 p d5 a5 eb5 d5 d5 d5 d5) (5q d6 mf cs5 d6 cs5 d6 q cs5 - - cs5 p 5q d5 eb5 c5 b4 d5))

length-subdivision
This function is able to divide a list of lengths into a number of subdivisions derived from a given length segment value. The :type and :position option increases the control for the desired result. When processing the omn-form sequence an optional third value allows you to fill intervalic steps (a root transposition) to new length values derived from the divisions. This function is a more sophisticated version of LENGTH-DIVIDE. It produces fascinating variants on the simplest of note-lengths, as can be seen below.

(setf rhy '(1/4 1/4 1/4 1/4)) (length-subdivision '(2 1/8) rhy) => (1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8)
position 's (start):
(length-subdivision '(2 1/16) rhy :position 's) => (1/16 1/16 1/8 1/16 1/16 1/8 1/16 1/16 1/8 1/16 1/16 1/8)
position 'e (end):
(length-subdivision '(2 1/16) rhy :position 'e) => (1/8 1/16 1/16 1/8 1/16 1/16 1/8 1/16 1/16 1/8 1/16 1/16)
type 'r (rest), position 'e (end):
(length-subdivision '(2 1/16) rhy :type 'r :position 'e) => (-1/8 1/16 1/16 -1/8 1/16 1/16 -1/8 1/16 1/16 -1/8 1/16 1/16)
type 'r (rest), position 's (end):
(length-subdivision '(2 s) rhy :type 'r :position 's) => (1/16 1/16 -1/8 1/16 1/16 -1/8 1/16 1/16 -1/8 1/16 1/16 -1/8)
type at random, rest or note :
(length-subdivision '(2 s) rhy :type '? :position 's) => (1/16 1/16 -1/8 1/16 1/16 -1/8 1/16 1/16 -1/8 1/16 1/16 1/8)
position and type at random:
(length-subdivision '(1 e) rhy :type '? :position '? :seed 34) => (1/16 1/8 1/16 1/8 1/8 -1/8 1/8 1/8 1/8) (length-subdivision '((2 5q) (1 3q)) rhy :type '? :position 's :seed 34) => (1/20 1/20 3/20 1/12 -1/6 1/20 1/20 3/20 1/12 -1/6) (length-subdivision '((2 5q) (1 3q) (1 e) (1 s)) rhy :seed 34) => (1/20 1/20 3/20 1/12 1/12 1/12 1/8 1/8 3/16 1/16)
Example:
(setf rhy2 '((1/4 1/4 1/4 1/4) (1/4 1/4 1/4 1/4))) (length-subdivision '(1 e) rhy2 :seed 34) => ((1/8 1/8 1/16 1/8 1/16 1/8 1/8 1/8 1/8) (1/16 1/8 1/16 1/8 1/8 1/8 1/8 1/8 1/8)) (length-subdivision '((1 e) (1 3q)) rhy2 :seed 34) => ((1/8 1/8 1/12 1/12 1/12 1/8 1/8 1/6 1/12) (1/16 1/8 1/16 1/6 1/12 1/8 1/8 1/6 1/12)) (length-subdivision '(((1 e)) ((1 3q))) rhy2 :seed 34) => ((1/8 1/8 1/16 1/8 1/16 1/8 1/8 1/8 1/8) (1/12 1/12 1/12 1/6 1/12 1/12 1/6 1/6 1/12)) (length-subdivision '((3 3q) (1 e)) '((q -e e h) (s e. q h)) :seed 65) => ((1/12 1/12 1/12 -1/8 1/8 1/12 1/12 1/12 1/4) (1/16 3/16 1/8 1/8 1/8 1/12 1/12 1/12 1/8)) (length-subdivision '(((3 3q)) ((1 e))) '((q -e e h) (s e. q h)) :seed 65) => ((1/12 1/12 1/12 -1/8 1/8 1/12 1/12 1/12 1/4) (1/16 1/16 1/8 1/16 1/8 1/16 1/8 3/8)) (length-subdivision '(((2 3q)) ((1 e))) '((q -e e h) (s e. q h)) :type '? :seed 65) => ((1/12 1/12 1/12 -1/8 1/8 1/12 1/12 -1/3) (1/16 -1/16 1/8 1/8 1/8 1/8 3/8))
OMN:
(setf mat1 '(q c4 d4 e4 f4 g4 a4 b4)) (length-subdivision '(1 e) mat1 :seed 45) => (s cs4 e b3 s d4 e cs4 e4 s f4 e fs4 s d4 e fs4 eb4 f4 a4 bb4 gs4 bb4 a4)
The symbol 'r (third value) will apply repeat function:
(length-subdivision '(1 e r) mat1 :seed 45) => (s c4 e s e d4 d4 s e4 e s e f4 f4 g4 g4 a4 a4 b4 b4)
Here we define the intervals (third value):
(length-subdivision '(1 e (13 0 13 0)) mat1 :seed 45) => (s cs5 e c4 s cs5 e eb5 d4 s f5 e e4 s f5 e fs5 f4 gs5 g4 bb5 a4 c6 b4) (length-subdivision '(4 s (13 0 13 0)) mat1 :seed 45) => (s cs5 c4 cs5 c4 eb5 d4 eb5 d4 f5 e4 f5 e4 fs5 f4 fs5 f4 gs5 g4 gs5 g4 bb5 a4 bb5 a4 c6 b4 c6 b4) (length-subdivision '(2 3q (13 0 13 0)) mat1 :type '(r n) :seed 45 :position '(e s s s e s s)) => (-3q cs5 c4 eb5 d4 eb5 f5 e4 - fs5 f4 fs5 - gs5 g4 bb5 a4 bb5 c6 b4 -) (setf mat2 '((e c4 p e4 mp g4 he c5 p) (q c4 f c4 cs4 mp - d5 p d5) (q cs5 mf = - - cs5 p =))) (length-subdivision '((1 e (13 0 13 0)) (2 e (13 0 13 0)) (2 3q (13 0 13 0))) mat2 :type '? :seed 34) => ((e c4 p e4 mp g4 q cs6 p e c5 q cs6) (e cs5 f c4 cs5 c4 -3q d5 mp cs4 -q e eb6 p d5 eb6 d5) (-s e cs5 mf -s e d6 cs5 -q - 3e d6 p 3q cs5 d6 3e cs5 e d6 cs5)) (length-subdivision '(((1 e (13 0 13 0))) ((2 s (13 0 13 0))) ((2 3q r))) mat2 :type '? :seed 34) => ((e c4 p e4 mp g4 q cs6 p e c5 q cs6) (e cs5 f s c4 cs5 -e s cs5 c4 e d5 mp s cs4 d5 -q -s eb6 p d5 - eb6 d5 eb6 d5) (3q cs5 mf cs5 cs5 cs5 cs5 cs5 -q - 3q cs5 p cs5 - - cs5 cs5))
In the example below we assign three series of values to variables s1, s2 and s3:
(setf s1 '(2 e (6 12 18 24)) s2 '(1 3q ((13 1 13 0) (13 0 7 1) r)) s3 '(3 5q ((13 0 13 0 13) ?)) ) (length-subdivision (list s1 s2 s3) mat2 :seed 23) => ((e c4 p 3e bb4 mp 3q e5 e cs6 cs5 p cs6 q.) (e fs4 f c5 3q cs5 cs4 cs5 5h mp 5q c4 g4 c4 -q e c4 p c4 3q d5 3h cs4) (e g5 mf cs6 3q d6 3h d5 -q - 5q d6 p cs5 cs5 5h e d6 cs5))

length-syncopate
The function LENGTH-SYNCOPATE is a valuable way of bringing more rhythmic interest into a length list. The usual idea of syncopating rhythm is to 'choke' certain attacks so that the attack is delayed or pre-empted.
(setf rhy '(1/4 1/4 1/4 1/4)) (length-syncopate '(1 4) rhy) => (1/4 3/16 1/16 1/4 1/4) (length-syncopate '(2 4) rhy) => (1/16 3/16 1/4 3/16 1/16 1/4)
Example:
(length-syncopate '(1 4) '(1/4 -1/8 1/16 1/16 -1/8 1/8 1/1) :seed 34) => (1/4 -1/8 1/16 1/64 3/64 -1/8 1/8 1)
In the example above only 1 length is divided by 4 (1, 3) - that is the 1/16. In the example below 2 values are divided by 3: (1, 2) and (2, 1).
(length-syncopate '(2 3) '(1/4 -1/8 1/16 1/16 -1/8 1/8 1/1) :seed 34) => (1/4 -1/8 1/48 1/24 1/16 -1/8 1/8 2/3 1/3) (length-syncopate '(1 4) '(1/4 -1/8 1/16 1/16 -1/8 1/8 1/1) :set 1/8 :seed 34) => (1/4 -1/8 1/16 1/16 -1/8 1/32 3/32 1)
Example with :set for each list:
(length-syncopate '((2 3) (1 4)) '((1/4 -1/8 1/16 1/16) (1/32 -3/32 1/8 1/1)) :set '(min 1/8) :seed 45) => ((1/4 -1/8 1/24 1/48 1/24 1/48) (1/32 -3/32 3/32 1/32 1)) (length-syncopate '((2 3) (1 5)) '((q -e s s) (s -e. q h)) :set 'max :ignore 'h :seed 65 :omn t) => ((3h 3q -e s 3s 3e) (s -e. 5q 5w h))
OMN:
(setf mat '(q c4 d4 e4 f4 g4 a4 b4)) (length-syncopate '(3 4) mat :seed 12) => (s b3 e. cs4 q d4 e. fs4 s d4 q f4 g4 a4 e. bb4 s c5)
Here we use a set of interval values:
(length-syncopate '(3 4 ((13 0) (0 14) (1 13))) mat :seed 23) => (s cs5 e. c4 d4 s e5 q e4 f4 s gs4 e. gs5 q a4 b4) (setf mat2 '((e c4 p e4 mp g4 he c5 p) (q c4 f c4 cs4 mp - d5 p d5) (q cs5 mf = - q cs5 stacc p = =)) (length-syncopate '((1 3 (-3 6)) (2 4 (6 0)) (2 5 (11 13))) mat2 :seed 34) => ((e c4 p e4 mp 3e 3q cs5 he c5 p) (q c4 f s fs4 e. c4 q cs4 mp - e. gs5 p s d5 q) (q cs5 mf cs5 - 5w c6 stacc 5q d6 stacc q cs5 p 5q c6 5w d6 q cs5))

polygon-rhythm
In the next three examples below we use a list of fixed polygon sides (non-symmetrical):
(circle-rhythm-plot (polygon-rhythm '(1 6 10) 16 1) :points 16) To rotate the polygon we change the starting point value:
(circle-rhythm-plot (polygon-rhythm '(1 6 10) 16 2) :points 16) (circle-rhythm-plot (polygon-rhythm '(0 2 5 7 10 12 13 15 16 18 19 21 23) 24 0) :points 24 :value 1/24)
Best wishes,
JP

• The function LENGTH-DIVIDE and friends are a useful device for introducing some rhythmic variation to some material. However, when the processed sequence is a full OMN expression (see example below), then the added notes cause all other parameters to shift forward (additional parameters are added at the end by looping). For introducing only a slight variation to some existing material (e.g., motif) these functions are therefore not so useful, because this shift of all parameters to basically "fill" the new added notes with pitches etc. greatly change the varied material for a listener.
(length-divide 1 2 '(q f3 leg+m1 q ab3 leg e c4 leg bb3 leg ab3 leg g3))
Basically, this is the opposite situation of the situation addressed by swallowing. Swallowing (e.g., with GEN-SWALLOW and the swallow argument of many other functions) avoids the shift of parameters like pitch etc. that would result from removing notes and turning them into rests. For addressing the situation above properly we would need something like the opposite of swallowing, some way to fill in parameters like pitch etc. for new notes to avoid shifting existing notes. I hope my explanation makes sense and you can see why something like the opposite of swallowing would be useful for functions that add notes to some input material.

Now, the tricky question is of course, what parameters (pitch etc.) should be added in such cases. Musically useful and common in the classical literature would be, e.g., repeating the parameters (pitch etc.) of the predecessor note (though that might be a bit too simplistic and annoying at times) or somehow interpolating some pitch gap between the previous and next note with a little scale or arpeggio and only repeating the other parameters like articulations (resulting in some variation that is likely most similar to the input material, so it would be good to have that as an option).  If the pitch interval between the two original notes is too small to add some pitch in between for the new now (or as an option in general for variety), it would also be good  to add some ornamentation (e.g., using PITCH-ORNAMENT), but for a close similarity between the original material and the variation it would be best as an option to apply such ornamentation only to the newly added notes, not all notes. Of course, other options could also be useful for variations that vary the input material a bit more strongly, e.g., some random pitch for the new notes within certain interval bounds.

Does some function that kind of is the opposite of GEN-SWALLOW in that it adds parameters like pitches for subdivided rhythmic values (to avoid the shifting) sound like a good idea?

The idea with the interpolation of gaps could be implemented by turning the original duration values and pitches into some envelope and then reading that envelope with the new rhythmic values. So, that is rather strait forward. However, that would not allow for some ornamentation, because such algorithm would not recognise which notes are new that should be ornamented.

Any other idea perhaps? Thanks!
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