LINUX Beta Test App 4.55 available

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Bernd Machenschalk
Bernd Machenschalk
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9 Apr 2006 11:04:42 UTC
Topic 13313
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    As some of the results of the previous 4.51 Beta Test App failed validation, I put this one with slightly modified vector code (non-SSE machines should not be affected) on the Beta Test Page. Please test and report!

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    Bernd Machenschalk
    Bernd Machenschalk
    Joined: 15 Oct 04
    Posts: 2,684
    Credit: 25,950,161
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    LINUX Beta Test App 4.55 available

    25 Apr 2006 14:32:21 UTC
    Message 2819
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      Quote:
      ey, since a fortnight has passed, I was wondering if there are any news on that front? Bernd, have you managed to integrate akosf's suggestion or are there more obstacles to it?


      I have just come back from two weeks travel. Having looked into (some of) the invalid results from the 4.55 App I found that the sin/cos precision is probably not the reason for them being invalid. I'm looking into this.

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      Bernd Machenschalk
      Bernd Machenschalk
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      Credit: 25,950,161
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      RE: Any idea when a

      2 May 2006 22:11:16 UTC
      Message 2820
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        Quote:
        Any idea when a solution might be implemented?


        I'm working on it.

        This problem seems to be unavoidable with that whole category of code, regardless of the vector unit used - may it be SSE, AltiVec or VIZ - everything that at a certain point is limited to single precision arithmetic.

        I'm currently trying to find out how important the error is scientifically. If it turns out to be neglectable, we would still have to change the validator quite a bit - it's not just tuning of parameters, but adding new features to it - to make it pass such results.

        For the x86-based platforms I intend to publish an App rather soon that has been partly coded in assembler and shouldn't have that problem - hopefully.

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        Bernd Machenschalk
        Bernd Machenschalk
        Joined: 15 Oct 04
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        Credit: 25,950,161
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        I'm not sure either. Because

        12 May 2006 12:35:36 UTC
        Message 2821
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          I'm not sure either. Because of the problems you're seeing as invalid, though successful results I think this App will never become the official one, at least not with other people outside Einstein@Home having looked at the code as well as the results.

          I'm currently coding a assembler version that is even faster while still keeping enough precision and which is meant to become the basis for all x86 based platforms. I got hold up on this by various problems and other tasks (and a bit of vacation, too), but that's the way the official Apps will probably go.

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          Bernd Machenschalk
          Bernd Machenschalk
          Joined: 15 Oct 04
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          RE: Thank you, Bernd, for

          19 May 2006 6:16:45 UTC
          Message 2822
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            Quote:
            Thank you, Bernd, for getting back at us. Reading your profile, I thought that you are responsible for the windows port. Yet, from your postings and sitting together with Akos it seems you are becoming (have become?) the chief master coder ;-)


            Well, I've been responsible for the Apps (i.e. the client-side code) since about the time the project went public last year (and before I last edited my profile...), but by far the most effort was necessary to port our program - that was originally designed to run on *nix clusters - to Windows.

            Quote:
            When you talk about the "basis for all x86 based platforms" do you mean that there will be also some modified apps for say SSE, 3DNow! and SSE3 extensions, which can be expected in the future (e.g. S5)?


            We will keep the principle of one single executable that detects the CPU it is running on and internally calls code that is optimized for this type of CPU. At least regarding the "official", automatically downloaded Apps there should be no need for the user to find out which CPU he has in his "computer" and chose between different Apps himself. In the current (Linux and PPC Mac) Apps we use a scheme that can easily be extended to more than the two types of CPU we currently distinguish.

            The next Linux Beta App (that's currently in internal testing) will still use SSE (when available). We don't gain anything from SSE2 (over SSE) and MMX doesn't serve our purpose at all, but I'm right now looking at what we may get from 3DNow!. If it should turn out that SSE3 also gives a noticable improvement I'd be happy to include some code for that as well.

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            Bernd Machenschalk
            Bernd Machenschalk
            Joined: 15 Oct 04
            Posts: 2,684
            Credit: 25,950,161
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            The next Linux Beta Test App

            19 May 2006 14:03:01 UTC
            Message 2823
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              The next Linux Beta Test App 4.58 is available, hopefully closing this thread. See here.

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