npmap.clj

; MPI kind macros
(defmacro BLOCK_LOW [i p n] `(int (/ (* ~i ~n) ~p)))
(defmacro BLOCK_HIGH [i p n] `(- (BLOCK_LOW (+ 1 ~i) ~p ~n) 1))
(defmacro BLOCK_SIZE [i p n] `(- (BLOCK_LOW (+ 1 ~i) ~p ~n) (BLOCK_LOW ~i ~p ~n)))
(defmacro BLOCK_ONWER [j p n] `(int (/ (- (* (inc ~j) ~p) 1) ~n)))
 
(defn partition-work
[p coll]
(let [s (seq coll)
n (count s)]
(loop [w [] s s i 0]
(if (< i p)
(let [block-size (BLOCK_SIZE i p n)]
(recur (conj w (take block-size s)) (drop block-size s) (inc i)))
(seq w)))))
 
(defn npmap [p f coll]
(apply concat
(pmap #(doall (map f %))
(partition-work p coll))))