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Is there a code that i can run to check the stability, if i have a lot of time to spare and a fast computer with a lot of memory? Do the codes use GPU for their

by ftxbro 3y ago

Is there a code that i can run to check the stability, if i have a lot of time to spare and a fast computer with a lot of memory? Do the codes use GPU for their Lanczos things yet?

bazzargh 3y ago
GPU? I was writing this stuff _30 years ago_. You were lucky to have a soundblaster. Everyone I knew who worked on this is long retired or passed away. AFAIK the code isn't available, that just wasn't how things worked back then, there were some ftp sites but open source was still nascent (Linux didn't exist yet). The architecture I was writing for was a Parsytec Supercluster https://en.wikipedia.org/wiki/Parsytec https://en.wikipedia.org/wiki/Parsytec which doesn't exist as a thing any more, it was mostly straight K&R C tho with a harness written in Occam, controlled from a workstation running SunOS (not even Solaris). If you happened to find the code it'd be completely worthless. Like I said above, we weren't able to use off the shelf, optimised matrix libraries because of the way we were generating coefficients on the fly, for what was a very sparse matrix. It's just not how you'd do it on modern hardware.
- ftxbro 3y ago
  I meant more like the code they are using these days for that same problem of ab initio oxygen isotopes or whatever it would be called. I know they didn't use GPU for things until recently, like maybe even now they haven't converted it yet.
  - jacquesm 3y ago
    You can bet that the people that need that kind of compute power are aware of the available options, they're not exactly stupid (to put it mildly).
    - ftxbro 3y ago
      Yeah you would think, which is why I was wondering "is there a code that i can run to check the stability" but apparently that's a silly thing to ask for some reason.
      - jacquesm 3y ago
        I don't think there is such a thing as a silly question but consider this: it's not just 'running the code', you need to actually understand the problem and short of a career in physics you're looking at 'numbers in that make no sense to you' and 'numbers out that make no sense to you'. To be able to meaningfully contribute you'd have to do a ton of groundwork first and then by the time you're ready to put your GPU goodies to work you'll probably find that path well trodden by others. For instance: https://ieeexplore.ieee.org/document/5763440 https://ieeexplore.ieee.org/document/5763440
        ftxbro 3y ago
        > I don't think there is such a thing as a silly question but consider this: it's not just 'running the code', you need to actually understand the problem and short of a career in physics you're looking at 'numbers in that make no sense to you' and 'numbers out that make no sense to you'. ok but what if the numbers do make sense to me tho, maybe i'm a computational physicist in some other area but not that one > by the time you're ready to put your GPU goodies to work you'll probably find that path well trodden by others yes that's what i was asking, what are the codes that others who have trodden that path are using
        ftxbro 3y ago
        > For instance: https://ieeexplore.ieee.org/document/5763440 https://ieeexplore.ieee.org/document/5763440 > Our GPU implementation shows a speedup up to 97.3 times over Matlab Implementation and 2.89 times over the Intel Math Kernel Library implementation on a Intel Core i7 920 Processor Interesting it's only 3x as fast on GPU as MKL on CPU I wonder how it compares to OpenBLAS. Oh but it's 2011 before GPU had really popped off, especially for larger precision. Probably in 2023 there is bigger GPU benefit vs. CPU.

by ftxbro 3y ago

Is there a code that i can run to check the stability, if i have a lot of time to spare and a fast computer with a lot of memory? Do the codes use GPU for their Lanczos things yet?

bazzargh 3y ago

GPU? I was writing this stuff _30 years ago_. You were lucky to have a soundblaster. Everyone I knew who worked on this is long retired or passed away. AFAIK the code isn't available, that just wasn't how things worked back then, there were some ftp sites but open source was still nascent (Linux didn't exist yet). The architecture I was writing for was a Parsytec Supercluster https://en.wikipedia.org/wiki/Parsytec https://en.wikipedia.org/wiki/Parsytec which doesn't exist as a thing any more, it was mostly straight K&R C tho with a harness written in Occam, controlled from a workstation running SunOS (not even Solaris). If you happened to find the code it'd be completely worthless. Like I said above, we weren't able to use off the shelf, optimised matrix libraries because of the way we were generating coefficients on the fly, for what was a very sparse matrix. It's just not how you'd do it on modern hardware.

ftxbro 3y ago
I meant more like the code they are using these days for that same problem of ab initio oxygen isotopes or whatever it would be called. I know they didn't use GPU for things until recently, like maybe even now they haven't converted it yet.
- jacquesm 3y ago
  You can bet that the people that need that kind of compute power are aware of the available options, they're not exactly stupid (to put it mildly).
  - ftxbro 3y ago
    Yeah you would think, which is why I was wondering "is there a code that i can run to check the stability" but apparently that's a silly thing to ask for some reason.
    - jacquesm 3y ago
      I don't think there is such a thing as a silly question but consider this: it's not just 'running the code', you need to actually understand the problem and short of a career in physics you're looking at 'numbers in that make no sense to you' and 'numbers out that make no sense to you'. To be able to meaningfully contribute you'd have to do a ton of groundwork first and then by the time you're ready to put your GPU goodies to work you'll probably find that path well trodden by others. For instance: https://ieeexplore.ieee.org/document/5763440 https://ieeexplore.ieee.org/document/5763440
      - ftxbro 3y ago
        > I don't think there is such a thing as a silly question but consider this: it's not just 'running the code', you need to actually understand the problem and short of a career in physics you're looking at 'numbers in that make no sense to you' and 'numbers out that make no sense to you'. ok but what if the numbers do make sense to me tho, maybe i'm a computational physicist in some other area but not that one > by the time you're ready to put your GPU goodies to work you'll probably find that path well trodden by others yes that's what i was asking, what are the codes that others who have trodden that path are using
      - ftxbro 3y ago
        > For instance: https://ieeexplore.ieee.org/document/5763440 https://ieeexplore.ieee.org/document/5763440 > Our GPU implementation shows a speedup up to 97.3 times over Matlab Implementation and 2.89 times over the Intel Math Kernel Library implementation on a Intel Core i7 920 Processor Interesting it's only 3x as fast on GPU as MKL on CPU I wonder how it compares to OpenBLAS. Oh but it's 2011 before GPU had really popped off, especially for larger precision. Probably in 2023 there is bigger GPU benefit vs. CPU.