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Why can I Debug some Numerical Programs that You Can’t? Why should we care?

cs.berkeley.edu

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Why can I Debug some Numerical Programs that You Can’t? Why should we care?

#1
Abstract: The future promises teraflops and terabytes in your laptop, petaflops and petabytes in your supercomputer, and the inability to debug numerical programs on either. Why can’t they be debugged? What should we do instead?

Why can I Debug some Numerical Programs that You Can’t? Why should we care?
cs.berkeley.edu

Re: Why can I Debug some Numerical Programs that You Can’t? Why should we care?

#4

Is it infeasible to use something other than floats for such computations? There are many schemes for dealing with bigintegers, bigdecimals and such with reasonable performance.

There are some simulations that squeeze everything they can out of a GPU or a cluster or a TOP500 machine. And I don't think arbitrary precision can be done easily on a GPU; if someone knows more, I'd love to be corrected on this one.

Re: Why can I Debug some Numerical Programs that You Can’t? Why should we care?

#5
Is there any reason this is marked as scribd, when the link goes to a normal PDF? Usually I avoid scribd documents, but I noticed that the link didn't go to scribd.

[Apologies that this is Offtopic, but I was unsure where to post this question].

Re: Why can I Debug some Numerical Programs that You Can’t? Why should we care?

#6
post #3

As someone who doesn't typically have reason to use either -- is using floats rather than doubles actually common? I was under the impression this was pretty rare.

It's not rare at all. A double takes up twice as much memory as a float and memory bandwidth is a precious commodity these days. If you have a lot of numbers (e.g. in 3D models or similar) and don't need the extra precision, using floats is an obvious choice.

Re: Why can I Debug some Numerical Programs that You Can’t? Why should we care?

#7
post #3

As someone who doesn't typically have reason to use either -- is using floats rather than doubles actually common? I was under the impression this was pretty rare.

Most video games use floats. This is because doubles will be emulated in software on some platforms, thus making them incredibly slow. The Unreal Engine, for example uses floats extensively.

Re: Why can I Debug some Numerical Programs that You Can’t? Why should we care?

#8
post #5

Is there any reason this is marked as scribd, when the link goes to a normal PDF? Usually I avoid scribd documents, but I noticed that the link didn't go to scribd. [Apologies that this is Offtopic, but I was unsure where to post this question].

Hacker News will automatically attach a scribd link to any pdf.

Re: Why can I Debug some Numerical Programs that You Can’t? Why should we care?

#9
post #5

Is there any reason this is marked as scribd, when the link goes to a normal PDF? Usually I avoid scribd documents, but I noticed that the link didn't go to scribd. [Apologies that this is Offtopic, but I was unsure where to post this question].

It's not marked as scribd - there is an alternate link to a scribd version of the pdf. All pdfs have this extra link.

(Scridb is a ycombinator company.)

Re: Why can I Debug some Numerical Programs that You Can’t? Why should we care?

#10
post #5

Is there any reason this is marked as scribd, when the link goes to a normal PDF? Usually I avoid scribd documents, but I noticed that the link didn't go to scribd. [Apologies that this is Offtopic, but I was unsure where to post this question].

That's not a tag, the [scribd] is a separate link to a scribd version of the pdf.
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