mtx.clj

(defprotocol MatrexOps
  (like [_ r c]) 
  (viewSelection [_ r c]))

;; Here's where the problem lies.  There is no level of abstraction higher than an abstract class (i.e. no interfaces)
;; but I still want to use the Parallel Colt 2D matrix impl.  The CernOps protocol would define a delegation layer 
;; intended to be used for PColt libs that expect an AbstractMatrix.
;; 
(defprotocol CernOps
  (cardinality [_]) 
  ;; ... a bunch more
  (setQuick [_ r c v]))

(deftype Matrex [matrex] ;; name it differently so as not to clash
  MatrexOps
  (like [r c] nil)
  (viewSelection [r c] nil)

  CernOps
  (cardinality [] 42)
  ;; ... a bunch more
  (setQuick [r c v] (.setQuick matrex r c v))

  clojure.lang.ISeq
  ;; ...

  clojure.lang.Counted
  (count [] (.rows matrex))
  )

;; Creates a closed instance of a concrete impl of AbstractMatrix
(defn matrex
  [r c] 
  (let [m (cern.colt.matrix.tdouble.impl.DenseColDoubleMatrix2D. r c)] ;; Million dollar question: should this be locked in a cell?
    (Matrex m)))                                                       ;; ... my instincts say yes.

(def m (matrex 3 3))
(setQuick m 0 0 Math/PI)
m  
                                        ; #:Matrex{:matrex #<DenseColDoubleMatrix2D 3 x 3 matrix
                                        ; 3.141593 0 0
                                        ; 0 0 0
                                        ; 0 0 0>}

(cardinality m)                         ;=> 42
(count m)                               ;=> 3

(.setQuick m 0 1 9)
m
                                        ; #:Matrex{:matrex #<DenseColDoubleMatrix2D 3 x 3 matrix
                                        ; 3.141593 9 0
                                        ; 0        0 0
                                        ; 0        0 0>}