gen-sym-markov

;;;;small function -> create symmetrical lists (palindrom) with markov (for generating half-seq)

(setf transition
      '((1 (4 1) (5 1) (-6 2))
        (2 (5 2) (4 1))
        (3 (4 1))
        (4 (5 1) (2 1))
        (5 (1 3) (-6 2) (4 1))
        (-6 (4 1) (3 2))
        (7 (1 1) (-6 1))))

;;;FUNCTION

(defun gen-sym-markov (&key seq-length transition-matrix) 
 (let ((vals 0))
   ;falls seq-length = liste, werden positive werte gezählt und neu
   ;seq-length (= angepasst, formatunabhängig)
   (if (listp seq-length)
     (setq seq-length (car (last (loop for i in seq-length
                                   with cnt = 0
                                   when (> i 0)
                                   collect (incf cnt))))))
   ;entscheindung grad/ungrad
   (if (evenp seq-length)
     (progn 
       (setq vals (gen-markov-from-transitions transition-matrix :size (/ seq-length 2) :start (rnd-pick (flatten (filter-first 1 transition-matrix)))))
       (append vals (reverse vals)))

     (progn 
       (setq vals (gen-markov-from-transitions transition-matrix :size (/ (- seq-length 1) 2) :start (rnd-pick (flatten (filter-first 1 transition-matrix)))))
       (append vals (list (rnd-pick (flatten (filter-first 1 transition-matrix)))) (reverse vals))))))


;;;;EXAMPLE

(gen-sym-markov :seq-length 8 :transition-matrix transition)