What is the best way to translate the generation of a multidimensional cell array from Matlab to Clojure -

i'm halfway through figuring out solution question, have feeling won't efficient. i've got 2 dimensional cell structure of variable length arrays constructed in non-functional way in matlab convert clojure. here example of i'm trying do:

pre = cell(n,1); aux = cell(n,1); i=1:ne   j=1:d     k=1:length(delays{i,j})         pre{post(i, delays{i, j}(k))}(end+1) = n*(delays{i, j}(k)-1)+i;         aux{post(i, delays{i, j}(k))}(end+1) = n*(d-1-j)+i; % takes account delay     end;   end; end; 

my current plan implementation use 3 loops first initialized vector of n vectors of empty vector. each subloop initialized previous loop. define separate function takes overall vector , subindices , value , returns vector updated subvector.

there's got smarter way of doing using 3 loop/recurs. possibly reduce function simplifies syntax using accumulator.

i'm not 100% sure understand code doing (i don't know matlab) might 1 approach building multi-dimensional vector:

(defn conj-in   "based on clojure.core/assoc-in, vectors instead of maps."   [coll [k & ks] v]   (if ks     (assoc coll k (conj-in (get coll k []) ks v))     (assoc coll k v)))  (defn foo []   (let [w 5, h 4, d 3         indices (for [i (range w)                       j (range h)                       k (range d)]                   [i j k])]     (reduce (fn [acc [i j k :as index]]               (conj-in acc index                        ;; real work here                        (str j k)))             [] indices)))  user> (pprint (foo)) [[["000" "001" "002"]   ["010" "011" "012"]   ["020" "021" "022"]   ["030" "031" "032"]]  [["100" "101" "102"]   ["110" "111" "112"]   ["120" "121" "122"]   ["130" "131" "132"]]  [["200" "201" "202"]   ["210" "211" "212"]   ["220" "221" "222"]   ["230" "231" "232"]]  [["300" "301" "302"]   ["310" "311" "312"]   ["320" "321" "322"]   ["330" "331" "332"]]  [["400" "401" "402"]   ["410" "411" "412"]   ["420" "421" "422"]   ["430" "431" "432"]]] 

this works if indices go in proper order (increasing), because can't conj or assoc onto vector anywhere other one-past-the-end.

i think acceptable use make-array , build array via aset. why clojure offers access java mutable arrays; algorithms more elegant way, , need them performance. can dump data clojure vectors after you're done if want avoid leaking side-effects.

(i don't know of or other version performs better.)

(defn bar []   (let [w 5, h 4, d 3         arr (make-array string w h d)]     (doseq [i (range w)             j (range h)             k (range d)]       (aset arr j k (str j k)))     (vec (map #(vec (map vec %)) arr))))  ;yikes?