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scidata
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Big ARM systems

Thu Feb 11, 2016 3:31 pm

The pi is at one end of the ARM spectrum. Here's the other end:
https://connect.innovateuk.org/web/high ... o-the-core
"Self-education is, I firmly believe, the only kind of education there is" - Isaac Asimov

Heater
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Re: Big ARM systems

Thu Feb 11, 2016 4:29 pm

Cool.

But I think if they want to hit one exaflop with reasonable power efficiency they should use a dedicated parallel floating point design. Think Epiphany multi-core chips from Adapteva https://www.parallella.org/board/

Of course they will need a big ARM to go with every 16, 64 or however many core floating point chip.
Memory in C++ is a leaky abstraction .

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scidata
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Re: Big ARM systems

Thu Feb 11, 2016 5:15 pm

Many of the scientific projects (eg those huge desert telescopes) have integer-only crunching code. 64-bit integers can hold decent precision.
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Heater
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Re: Big ARM systems

Thu Feb 11, 2016 5:31 pm

Interesting.

The 64 bit floating point representation gives you 53 bit of integer range and, as far as I can tell be processed at the same speed as integer operations.

Generally super computers are using floats. That's what the measure their speed in FLOPS. Perhaps those astronomer guys, working at cosmological distances, need more integer range.

Not sure why that would be though. The observable universe is only 8.8e26 meters. Far short of 2 to the power 64, 18eE18.
Memory in C++ is a leaky abstraction .

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morphy_richards
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Re: Big ARM systems

Thu Feb 11, 2016 5:47 pm

I suppose stuff like this takes lots of modelling big numbers over lots of interactions between chunks of observable universe. Or something :?

Edit... Ps, wow! :shock:

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scidata
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Re: Big ARM systems

Thu Feb 11, 2016 5:52 pm

Actually, they may require both integer and float. I know the SKA is ruminating over this:
http://www.hpcwire.com/2015/06/04/shini ... uirements/

There's also the problem of processing pixelated images, which requires simple integer algorithms. The pi makes a wonderful experimentation platform to develop such algorithms.

As for gravitational waves, the pi has been on this for a while now:
http://www.einsteinathome.org/forum_thread.php?id=11209
"Self-education is, I firmly believe, the only kind of education there is" - Isaac Asimov

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scidata
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Re: Big ARM systems

Thu Feb 11, 2016 6:17 pm

"Self-education is, I firmly believe, the only kind of education there is" - Isaac Asimov

Heater
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Re: Big ARM systems

Thu Feb 11, 2016 6:25 pm

Oh yeah, gravity wave detection.

That is the biggest news for a long time.

I want to hear the signal they detected. According to a couple of physicists I have heard describing the gravity wave signals coming from colliding black holes they should make a chirp with a distinct upward sweep in frequency.
Memory in C++ is a leaky abstraction .

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GTR2Fan
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Re: Big ARM systems

Thu Feb 11, 2016 6:28 pm

Heater wrote:I want to hear the signal they detected. According to a couple of physicists I have heard describing the gravity wave signals coming from colliding black holes they should make a chirp with a distinct upward sweep in frequency.
Take a look on the BBC News website. They're sure to have a sound clip of it on there. I've heard it and it sounds like a single fart plop in a bath. :lol:
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Re: Big ARM systems

Thu Feb 11, 2016 7:02 pm

GTR2Fan,
I've heard it and it sounds like a single fart plop in a bath.
All of a sudden I went off the idea of hearing the gravity wave signal.

When you say "I've heard it" do you mean you have heard the actual signal in the news story? If so where? How?

Or do you mean one of the many audio simulations?

Edit:....

OK I found that black hole fart sound on the video in the BBC news story. I don't believe it's the real thing.

We could recreated using the graphs of the signals in the Nature story http://www.nature.com/news/einstein-s-g ... st-1.19361

Could be a job for sonic-pi :)
Memory in C++ is a leaky abstraction .

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scidata
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Re: Big ARM systems

Fri Feb 12, 2016 5:37 pm

From the Wolfram blog:
http://blog.wolfram.com/2016/02/11/on-t ... s-by-ligo/

BTW That blog has some good Raspberry Pi stories (I think Stephen Wolfram is a pi fan).
"Self-education is, I firmly believe, the only kind of education there is" - Isaac Asimov

mung
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Re: Big ARM systems

Sat Feb 13, 2016 7:28 pm

scidata wrote:The pi is at one end of the ARM spectrum. Here's the other end:
https://connect.innovateuk.org/web/high ... o-the-core
I remember suggesting something similar in one of early the 'next gen rpi specs' threads, I had a much better design in mind, and the iceotope cooling system looks sub optimal and nothing like I envisaged.

I think I jokingly named my idea a POOP sandwich, as it allowed multiple package on package stacking and orthogonal overlap allowing full bandwidth interconnect of 12 adjacent processors.

I am sure we are rapidly heading toward singularity now. :lol:

mung
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Re: Big ARM systems

Sat Feb 13, 2016 7:29 pm

Every time I hear the name Hanford I think 'most toxic place on earth' :cry:

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