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Programming-Idioms

  • D
  • Fortran
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Idiom #188 Matrix multiplication

Perform matrix multiplication of a real matrix a with nx rows and ny columns, a real matrix b with ny rows and nz columns and assign the value to a real matrix c with nx rows and nz columns.

uses typ, omv;
var
  A: array[1..m, 1..n] of ArbFloat;
  B: array[1..n, 1..p] of ArbFloat;
  C: array[1..m, 1..p] of ArbFloat;

...

omvmmm(
    A[1,1], m, n, n,
    B[1,1], p, p,
    C[1,1], p
  );
c = matmul (a,b)
(defn t [x] (apply (partial mapv vector) x))
(defn v* [u v] (reduce + (mapv * u v)))
(defn shape [a] (comp (partition-all (count a)) (map vec)))

(defn mm [a b]
    (into [] (shape a)
        (for [line a col (t b)]
            (v* line col))))

(def c (mm a b))

New implementation...