The attached patch should fix it. Tobias
On Sun, 20 Jan 2013 15:09:42 +0100, Jens Axel Søgaard <jensa...@soegaard.net> wrote:
Hi Berthold, 2013/1/20 Berthold Bäuml <berthold.bae...@dlr.de>:I tried a little test with mildly large Flonum matrices using math/matrix in Typed Racket. Two 1000x1000 dimensional matrices should be multiplied with (array- strictness #t). Running this in DrRacket results in an "out of memory" error (also having set the memory limit to 1GB) and running it with racket on the commandline makes the computer start to heavily swap.Where is this high memory consumption coming from?I consider this a bug in matrix*. The culprit is inline-matrix-multiply in "untyped-matrix-arithmetic.rkt". When multiplying an mxp matrix with an pxn matrix, it builds a temporary array of size n*p*m with all products needed, then it computes sums of these products. Replacing this algorithm with the standard O(n^3) ought to be easy. Numpy (and Mathematica, I believe) uses BLAS and LAPACK, which use Strassen's algorithm (or better?) for matrices this large, so there will still be a performance gap. If this performance gaps turns out to be too large, we must figure out a way to integrate BLAS and LAPACK bindings into math/matrix. For the time being, I have attached an implementation of math/matrix using supporting matrices over doubles (math/matrix supports matrices over Racket numbers). The implementation uses Racket bindings to BLAS and LAPACK. All names ought to the same, just replace "matrix" with "flmatrix". Your example becomes: #lang racket (require "flmatrix.rkt") (define dim 1000) (define big1 (build-flmatrix dim dim (lambda (i j) (random)))) (define big2 (build-flmatrix dim dim (lambda (i j) (random)))) (define res (time (flmatrix* big1 big2))) Note: Disable "Populate "compiled" directories (for faster loading)" to run it in DrRacket. To disable: Choose the language menu. Choose the menu item "Choose language". Click the button "advanced". Then disable. If it is enabled, I currently get this curious error from the compiler: ../collects/compiler/cm.rkt:438:6: write: cannot marshal value that is embedded in compiled code value: #<ctype:float> I unsure whether it is a bug in my code, or in cm.rkt.
-- --------------------------------------------------------- Tobias Hammer DLR / Institute of Robotics and Mechatronics Muenchner Str. 20, D-82234 Wessling Tel.: 08153/28-1487 Mail: tobias.ham...@dlr.de
flmatrix.patch
Description: Binary data
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