# a tiny function idea

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```(defun and-span (n a b)
(and (>= n a)
(<= n b)))

(and-span 13 12 45)
=> t

(and-span 2 12 45)
=> nil```

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• ### Similar Topics

• By spuki
Hallo,
newbie here 🙂
I'm just starting with OM and playing around with the tutorials.
I slightly changed tutorial #4 and run into something strange.

If i run the script as posted below, all works as expected. But when i change the function reverse to nreverse (and nreverse is the oficially documented name of the function)
the omn result will leave the right hand empty. Why ist that?  And why does reverse work as i expect it to work?

And, another thing: i dont understand what the term seed will do. Will it make random functions behave always the same as long as the seed is the same?
...and what does the number following the seed mean?

Thank you !!
Best,
Sebasian
(setf pitches (gen-repeat 5 '(c4 cs4 fs4 g4 c5 cs5))) (setf transposed-pitches (gen-repeat 5 (pitch-transpose -24 pitches))) (setf lengths (span pitches '(e))) (setf lengths-rests (length-weight lengths :weight '(2 1) :seed 12)) (setf left-lengths (reverse lengths-rests)) (setf piano-righthand       (make-omn        :length lengths-rests        :pitch pitches        :velocity'(mp))) (setf piano-lefthand       (make-omn        :length left-lengths        :pitch transposed-pitches        :velocity '(f))) (setf timesigs (get-time-signature left-lengths)) (def-score lesson-4            (:key-signature 'chromatic             :time-signature '( 5 8 )             :tempo 190             :layout (piano-layout 'piano-rh 'piano-lh))     (piano-rh    :omn piano-righthand    :channel 1    :sound 'gm    :program 'acoustic-grand-piano)     (piano-lh    :omn piano-lefthand)   )
• By Deb76
Hello,
Somewhat stupid question but I do not find a function that would allow me to reorder a sequence of pitches.
Let me explain, on a forum where Messiaen's limited transposition modes are discussed, I wanted to show that with Opumodus we could very easily analyze the modes and recreate them. I have no problem with those who are in total symmetry and divisible by two, but if I take the mode 3: (c4 d4 eb4 e4 gb4 g4 ab4 bb4 b4), using the function pitch-transpose-start I get in the end the mode but according to the postponement of the intervallic structure on c4 d4 ab4 is => ((c4 e4 gs4) (d4 fs4 bb4) (eb4 g4 b4)). I tried to reorder with the function pcs-normal-order the mode is reordered but with however the c4 in last position: (d4 eb4 e4 fs4 g4 gs4 bb4 b4 c4). Now, I suppose there is a function that makes it possible to obtain the right disposition. What is it ?
(setf modmessiaen3 '(c4 d4 eb4 e4 gb4 g4 ab4 bb4 b4)) (setf SIMessiaenMod3 (pitch-to-interval modmessiaen3)) ; =>  (2 1 1 2 1 1 2 1) (setf mod3divide (gen-divide 3 modmessiaen3)) (setf firstmodmessiaen3 (filter-first 3 modmessiaen3)) (setf report3 '(c4 e4 ab4)) (setf rep3 (gen-repeat 3 (list report3))) (setf pch3 (modus (flatten (pitch-transpose-start firstmodmessiaen3 rep3)))) (setf MessiaenMod3 (pcs-normal-order pch3 :pitch)) (setf SIMessiaenMod3a (pitch-to-interval MessiaenMod3)) ; => (1 1 2 1 1 2 1 -11) (setf mod3chordsM (melodize '((c4eb4gb4) (d4gb4bb4) (eb4gb4bb4) (e4g4b4) (gb4bb4db5) (g4b4d5) (ab4b4d5) (bb4gb5) (b4d5gb5)))) (setf analysechords3 (pcs-analysis (integer-to-pitch (modus mod3chordsM))))
In particular, this distorts the analysis of the interstellar structure of mode 3:
of (2 1 1 2 1 1 2 1) I get (1 1 2 1 1 2 1 -11)
Besides, there is probably a more efficient script than the one I tried?
Best.
Didier

PS : In fact, I realize that the function pcs-normal-order is not adapted at all according to the modes.

• In my Dissertation, I worked a way to convert every chord and set in a modulo 12 rhythm,
so the entire catalog of FORTE are converted to rhythms, following the steps of Babitt:

As a hardcore serialist, Babbitt was interested in converting 12-tone rows to rhythms, in a kind of 12-tone rhythm theory.
Below, Wuorinen show one example of a typical Babbitt idea:

For the sake of explaining my idea of function, it's important to have in mind that for Babbitt, the order of the
row is very important and lead to different results in the pitch to rhythm conversion. Take a look in the example
below:

In the preceeding figure, the order of the C major triad generate different rhythms. In the example (0 4 7) have a
different result from (4 0 7) or (7 0 4).

In the system I developed in my Dissertation, the order does NOT matter, since (0 4 7), (7 0 4) or (4 0 7) will result
in exactly the same rhythm, as you can see below:

In my system, the transposition equals rotation (as well as in Babbitt)

And every chord symbol can be transformed in a rhythm:

Even voicings can be converted in longer Rhythms (the more spread the voicing, the longer the rhythm):

So I did every FORTE SET in the catalog, in this way:
Below, you can see the example of the rhythm of the major triad (Forte number 3-11b).
In the 1st bar there is the prime form (0 4 7).
In each subsequent bar there is a rotation of the first set by 16th note increments.

HERE IS THE POINT, for the sake of the new function !

The note C (that I call Rhythmic Fundamental, the "root" of the rhythm) is being displaced, as
you can see in the circled notes.

THE SET WRAP AROUND ITSELF, always forming 12 time-points (always twelve 16th notes),
in a different way from Babbit, where the order of the sets generates longer rhythms.
THIS WAY IS MORE INTERESTING For Popular and Minimalist Repetition Music, as
well as 12 tone music.

In the bottom staff, there are the complementary rhythm of the 3-11b set, i.e., the 9-11a
set. In the catalog, every set is presented alongside its complementary set and every set is
presented in 3/4 (16th notes) and in 12-8 (with the 8th note as the base value for the increments
and rotations).

So the function needed would be the one that mirror exacty this kind of conversion, not the tradicional time-point-system conversion,
so I could use my catolog inside Opusmodus, connecting the diferent sets, like this:

Or even using portions of the Rhythmic Sets, by truncating some of them, like this:

In the preceeding example, only parts of the 2 sets are used (9 time points out of 12 in the
first and 8 time points out of 12 in the second).

So, I hope someone could help me to find a way of implementing this.
Maybe Janusz or Stephane could find interesting to develop this kind of idea inside
the software.

All the best !
Julio Herrlein
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