[racket] math/matrix

Where are you seeing the slowness in that code? For me the majority of
the time is spent in matrix-solve, and since that is another module it
doesn't matter what you write your module in.

In untyped racket, (set the first line to #lang
typed/racket/no-check), it is much slower. 36 seconds to create the
matrix instead 70 milliseconds.

Also as a side not you can run 'raco make matrix.rkt', and this will
typecheck and compile the code so that 'racket matrix.rkt' will do
less work at startup.


On Sat, May 10, 2014 at 9:09 PM, Eduardo Costa <edu500ac at gmail.com> wrote:
> The documentation says that one should expect typed/racket to be faster than
> racket. I tested the math/matrix library and it seems to be almost as slow
> in typed/racket as in racket. Here is the program in typed racket:
>
> #lang typed/racket ; file: matrix.rkt
> (require math/matrix)
>
> (: mx Index)
> (define mx 600)
>
> (: r (Index Index -> Flonum))
> (define (r i j) (random))
>
> (: A : (Matrix Flonum))
> (define A (build-matrix mx mx r))
>
> (: sum : Integer Integer -> Flonum)
> (define (sum i n)
>   (let loop ((j 0) (acc 0.0))
>     (if (>= j mx) acc
>         (loop (+ j 1) (+ acc (matrix-ref A i j))) )))
>
> (: b : (Matrix Flonum))
> (define b (build-matrix mx 1 sum))
>
> (let [(m (matrix-solve A b))]
>   (displayln (matrix-ref m 0 0)))
>
> You can run it thus:
>
> time racket matrix.rkt
>
> What should I do to speedup the above code?
>
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