I wrote a script to reproduce Steve Reich's "Clapping Music" by brute forcing a list of rhythm permutations. Is there a single command that would do the same?

;; ---------------------------------------------------------

;; Welcome to the Composer panel.

;; This is the space where you write your score.

;; ---------------------------------------------------------

(setf Clap1 '(e g4 e e -e e e -e e -e e e -e ))

(setf Clap2 '( ( e c4 e e -e e e -e e -e e e -e )

( e e -e e e -e e -e e e -e e )

( e -e e e -e e -e e e -e e e )

( -e e e -e e -e e e -e e e e )

( e e -e e -e e e -e e e e -e )

( e -e e -e e e -e e e e -e e )

( -e e -e e e -e e e e -e e e )

( e -e e e -e e e e -e e e -e )

( -e e e -e e e e -e e e -e e )

( e e -e e e e -e e e -e e -e )

( e -e e e e -e e e -e e -e e )

( -e e e e -e e e -e e -e e e )

( e e e -e e e -e e -e e e -e )))

(setf RepClap1 (gen-repeat (length Clap2) Clap1))

(ps 'gm

:p (list RepClap1 Clap2)

:time-signature '(6 4)

:tempo 160

)

This perhaps

(setf Clap2 (loop for i from 0 downto -12 collect (gen-rotate i (pitch-transpose -7 Clap1))))

less calculations:

(setf Clap3 (loop with clap = (pitch-transpose -7 Clap1) for i from 0 downto -12 collect (gen-rotate i clap)))

Or repeating every pattern 8 times.

((setf Clap3 (omn-to-measure (loop with clap = (pitch-transpose -7 Clap1) for i from 0 downto -12 collect (gen-repeat 8 (gen-rotate i clap))) 6/4))

Jesper

Solution:

(setf clap1 '(e g4 = = - = = - = - = = -))
(setf clap2 (gen-rotate 12 '(e c4 = = - = = - = - = = -) :type 'list))

or

(setf cl1 '(e g4 = = - = = - = - = = -))
(setf cl2 '(e c4 = = - = = - = - = = -))
(setf r-num (length (single-events cl2)))
(setf r-cl2 (gen-rotate (1- r-num) cl2 :type 'list))
(setf r-cl1 (gen-repeat (length r-cl2) (list cl1)))

(ps 'gm
    :p (list r-cl1 r-cl2)
    :time-signature '(6 4)
    :tempo 160
    )

quite simple to do :-)

Ah, type list. Neat.

Jesper

Thank you! I don't know why gen-rotate didn't show up in my search. I knew there was an elegant solution!

Also this solution, from Book 2:

;;;--------------------------------------------------------
;;; Study and Practice in Composition with Opusmodus - Book 2
;;; Julio Herrlein
;;; ISBN 9791280270566
;;; Score Examples (code)
;;;--------------------------------------------------------
;;; 2.4. Reich's Clapping Music - PCS-Rhythm
;;;--------------------------------------------------------
(progn
(setf cell 1)

;; Clap 1 Ostinato/Timeline Voice
(setf rhy1 (pcs-rhythm '8-26 :rotate 9))
(setf aug1 (length-augmentation 2 rhy1))
(setf rep1 (gen-repeat (* 13 cell) aug1))
(setf clap1-ostinato (omn-to-time-signature rep1 '(6 4)))

;; Clap 2 Variation Voice
(setf rhy2 (pcs-rhythm '8-26 :rotate '(9 8 7 6 5 4 3 2 1 0 11 10 9)))
(setf aug2 (length-augmentation 2 rhy2))
(setf rep2 (gen-repeat cell aug2))
(setf clap2-rotate (omn-to-time-signature aug2 '(6 4)))

;; To find the length of the repetitions
(get-count clap2-rotate :sum t)

;; Preview Score
(ps 'gm
:rhy (list clap1-ostinato clap2-rotate)
:key-signature '(c maj) :tempo 88 :time-signature '(12 8))
)