<div dir="ltr">Modification of the above to use FlVector did not show a difference.</div><div class="gmail_extra"> <div class="gmail_quote">On Sun, Jan 20, 2013 at 2:35 PM, Jens Axel Søgaard <<a href="mailto:jensaxel@soegaard.net" target="_blank">jensaxel@soegaard.net</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">2013/1/20 Berthold Bäuml <<a href="mailto:berthold.baeuml@dlr.de">berthold.baeuml@dlr.de</a>>: <div class="im">>> Ah! The Numpy example uses floats and not doubles. > > On my machine Numpy says it is using float64, hence, double. > <a href="http://big1.dtype.name" target="_blank">big1.dtype.name</a> -> float64 </div>Sorry for the confusion. I am used to the Racket documentation were float means single precision, so I misinterpreted the Numpy documentation. Also > numpy.random.random((5,5)) array([[ 0.04748764, 0.15242073, 0.2366255 , 0.86926654, 0.16586114], [ 0.33117124, 0.7504899 , 0.43179013, 0.1992083 , 0.83266119], [ 0.25741902, 0.36912007, 0.38273193, 0.29622522, 0.75817261], [ 0.49313726, 0.20514653, 0.45329344, 0.964105 , 0.77459153], [ 0.5267172 , 0.87269101, 0.34530438, 0.38218051, 0.05107181]]) suggested, that the numbers were single precision. It turns out that random only produces 53 bit random floats. Anyways, here is a standard matrix multiplication algorithm in Typed Racket. #lang typed/racket (require racket/unsafe/ops racket/flonum) (define-type NF Nonnegative-Fixnum) (: matrix* : (Vectorof Flonum) (Vectorof Flonum) Index Index Index -> (Vectorof Flonum)) (define (matrix* A B m p n) (define size (* m n)) (define: v : (Vectorof Flonum) (make-vector size 0.0)) (define index 0) (: loop-i : NF -> (Vectorof Flonum)) (define (loop-i i) (cond [( (loop-j i 0) (loop-i (+ i 1))] [else v])) (: loop-j : NF NF -> Void) (define (loop-j i j) (when (< j n) (loop-k i j 0 0.0) (set! index (+ index 1)) (loop-j i (+ j 1)))) (: loop-k : NF NF NF Flonum -> Void) (define (loop-k i j k sum) (define i*p (* i p)) (define k*n (* k n)) (cond [(< k p) (loop-k i j (+ k 1) (+ sum (* (unsafe-vector-ref A (+ i*p k)) (unsafe-vector-ref B (+ k*n j)))))] [else (vector-set! v index sum)])) (loop-i 0)) (define dim 200) (define A (build-vector (* dim dim) (λ (_) (random)))) (define B (build-vector (* dim dim) (λ (_) (random)))) (collect-garbage) (collect-garbage) (define A*B (time (matrix* A B dim dim dim))) /Jens Axel <div class="HOEnZb"><div class="h5"> ____________________ Racket Users list: <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> </div></div></blockquote></div> </div>