Re: [eigen] slides of my talk |

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*To*: eigen@xxxxxxxxxxxxxxxxxxx*Subject*: Re: [eigen] slides of my talk*From*: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>*Date*: Mon, 26 Jan 2009 16:50:41 +0100*Dkim-signature*: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type :content-transfer-encoding; bh=ryVGkitzoVNv0ixpfOFI4xM0HhvQKkppWkfBNR73aic=; b=Z9SrbAxTHnCTs10ieCziv1CO2c87ZnQTPmp/A9pDU8B5+v3nMkWs6pUnLqBtNGaXff VOVDQ+/JwMQVZtv8u3JiC0glzu+enpT3dE6nqcY6cQckMj7IVuroBmJ7cXIA8YsobMcw xfth2ZkYuuLSTWFWAixg3Pc7ul1S7ZuEOlSo4=*Domainkey-signature*: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; b=IBVE30V90PYoOnlGDcnCnskmZ0cchkt017yN+TyyhVZ/kvETOX4fSrx8kG6hWWLAmp e+OsgScOAzVBexsx2vPaCJyyCtgHdWLyKr0k9ygwZeXl6cH3Afhk03vm21jtAuHH/2Gn SftVXSTu6zb4FxOueyivrgcKQ/1cX7qtl1AXE=

Just FYI, if you want something that's guaranteed to kill matlab or more generally any framework focusing on dynamic-size objects, try a heavy computation on a large set of fixed-size vectors or matrices. E.g. take a 4x4 matrix m, take a large array of 4-vectors v[100000000]; and multiply each of these vectors by the matrix m; Benoit 2009/1/26 Andre Krause <post@xxxxxxxxxxxxxxxx>: > Gael Guennebaud schrieb: > > well, it seems as if there was something done by the matlab team since version > 6.5 of matlab. see this link: > > http://www.caspur.it/risorse/softappl/doc/matlab_help/techdoc/matlab_prog/ch7_pe11.html > > Operating System MATLAB 6.1 MATLAB 6.5 Performance Gain > Windows 1 min., 25.9 sec. 1.1 sec. x 78.1 > Linux 3 min., 13.8 sec. 1.7 sec. x 114.0 > Solaris 8 min., 51.0 sec. 23.5 sec. x 22.6 > > looking at those results, it would be even more interesting, how well matlab > does now compared to native c++. > > seems as if they indeed added some jit compiler... > > p.s. just googled - and found this: > > http://www.mathworks.se/products/matlab/whatsnew.html > > so matlab really has JIT acceleration. > > >> indeed, if you use matlab on relatively large dataset and you only use >> high level operators/routines then matlab is very fast because it >> relies on other state of the art library. There even exists plugins to >> perform some computations on the GPU... >> >> Said that, matlab is extremely slow as soon as you are doing some more >> low level stuff involving complex expressions or a lot of small >> computations... Matlab can be a couple of order of magnitude slower >> than a C/C++ equivalent code. It seems MatLab is missing a JIT >> compiler. >> >> btw, benoit thanks for the slides ! >> >> Gael. >> >> On Mon, Jan 26, 2009 at 3:35 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote: >>> I have no clue how matlab does in general, but on the forum we've had >>> a user benchmarking matrix product against matlab, and matlab was >>> doing like MKL and Goto, which suggests that it's using one of these >>> libraries. >>> >>> If you're on *nix, you could try ldd or nm to get a clue about what >>> library they're using. >>> >>> Cheers, >>> Benoit >>> >>> 2009/1/26 Andre Krause <post@xxxxxxxxxxxxxxxx>: >>>> Benoit Jacob schrieb: >>>>> Hi, >>>>> >>>>> Today morning I gave a talk on Eigen at the CS department. Here are my >>>>> slides, in case they might be helpful. >>>>> When you see (SHOW BENCHMARKS) that's where I showed the benchmark >>>>> graphs that are displayed on the Benchmark page of the wiki. >>>>> I didn't have time to cover the last part on Eigen internals, I just >>>>> finished with the benchmarks. However people were interested and asked >>>>> questions about internals so in effect I got to explain as much of the >>>>> internals as I had planned to. >>>>> >>>>> Thanks a LOT to Keir: he translated the C++ snippets into Matlab for >>>>> me, and gave me a good briefing as to how to organize a talk for an >>>>> audience of CS people. >>>>> >>>>> I am just afraid that using \documentclass{slides} for a public of CS >>>>> people makes me look like a dinosaur mathematician. >>>>> >>>>> Cheers, >>>>> Benoit >>>> dear benoit, you show matlab code corresponding to eigen2 code. but in the >>>> benchmark section on the wiki, there is no matlab benchmark. i would be very >>>> curious how slow (or fast?) matlab is, compared to eigen. i teached myself >>>> matlab over christmas, and now i am curious how matlab compares to c++ (with >>>> eigen2). >>>> >>>> >>>> >>> >>> >> >> >> > > > >

**Follow-Ups**:**Re: [eigen] slides of my talk***From:*Benoit Jacob

**References**:**[eigen] slides of my talk***From:*Benoit Jacob

**Re: [eigen] slides of my talk***From:*Andre Krause

**Re: [eigen] slides of my talk***From:*Benoit Jacob

**Re: [eigen] slides of my talk***From:*Gael Guennebaud

**Re: [eigen] slides of my talk***From:*Andre Krause

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