Chazykins
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Raspberry pi cluster

Tue Nov 08, 2016 7:27 am

Is am considering clustering 4 rpi3s together but would this create. 1 faster pi or would it work a different way.

Thank you in advance

fruitoftheloom
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Re: Raspberry pi cluster

Tue Nov 08, 2016 7:45 am

Chazykins wrote:Is am considering clustering 4 rpi3s together but would this create. 1 faster pi or would it work a different way.

Thank you in advance
Clusters are a great way to learn about Distributed Computing, it will not become a Super RPi.....

http://makezine.com/projects/build-a-co ... pi-cluster

http://www.widriksson.com/raspberry-pi-hadoop-cluster


Actually for the price of 4 RPi's and the extras could buy a brand new Tower PC:

http://www.ebay.co.uk/itm/Zoostorm-A6-3 ... 2704626779
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richrarobi
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Re: Raspberry pi cluster

Tue Nov 08, 2016 6:40 pm

Clusters are a great way to learn about Distributed Computing, it will not become a Super RPi....
I don't think fruitoftheloom entirely intended the 'Distributed' in the statement above. Apart from that one word I totally agree.....
However, Distributed Computing is what many of the fun things in IOT, etc, etc are about. i.e. loosely (as opposed to "tightly" in clustered computing) coupled computers working together. Doing their own thing, minding their own business and every so often responding to a request or message from another.
Be it from MQTT, ZMQ, or whatever, Anyone thinking about robotics should be interested in this.

An example in future robotics might be a "swarm" member sending its regular status update to "control"?
Distributed is fun....

fruitoftheloom
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Re: Raspberry pi cluster

Tue Nov 08, 2016 6:58 pm

richrarobi wrote:
Clusters are a great way to learn about Distributed Computing, it will not become a Super RPi....
I don't think fruitoftheloom entirely intended the 'Distributed' in the statement above. Apart from that one word I totally agree.....
However, Distributed Computing is what many of the fun things in IOT, etc, etc are about. i.e. loosely (as opposed to "tightly" in clustered computing) coupled computers working together. Doing their own thing, minding their own business and every so often responding to a request or message from another.
Be it from MQTT, ZMQ, or whatever, Anyone thinking about robotics should be interested in this.

An example in future robotics might be a "swarm" member sending its regular status update to "control"?
Distributed is fun....
Read the second link page, thank you :roll:

If you like Raspberry Pi’s and like to get into Distributed Computing and Big Data processing what could be a better than creating your own Raspberry Pi Hadoop Cluster?
adieu

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DavidS
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Re: Raspberry pi cluster

Tue Nov 08, 2016 7:16 pm

While it would be possible to take advantage of all 16 ARM cores and all 16 QPU cores, that would require custome written software, and would not be any use with Linux.

Though if you wish to play with doing such things in bare metal, one thing that would be likely possible is a pretty fast bare metal ray tracer, distributing the load between 16 ARM cores and 12 QPU's, only a small amount of data would have to be transfered between the 4 RPi's, and it would be a doable example of how such a system could have benifits.


Do it with 16 Raspberry Pi 3B's and you may even be able to achieve real time Ray Tracing, maybe.
RPi = The best ARM based RISC OS computer around
More than 95% of posts made from RISC OS on RPi 1B/1B+ computers. Most of the rest from RISC OS on RPi 2B/3B/3B+ computers

richrarobi
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Re: Raspberry pi cluster

Tue Nov 08, 2016 7:24 pm

Sorry, missed that second link, 'cos I didn't read it (I worked with (VAX) clusters (many) years ago and won't go there agin... Wasn't disagreeing with your sentiment, just that I think that there are so many confused people about .... They seem to get so excited about clusters and they don't know just how much overhead is involved with clustering normal processors. It is an interesting thing to do, but....

p.s. that word Distributed is being used in too many different contexts, and at too many different levels. I was comparing Distributed Computing with Cluster Computing. Distributed File Systems are (I believe) another use of the word. Reminds me of System Fault Tolerance in NetWare. SFT III ....Two NetWare servers acting as one..... each with their own copy of the whole environment (using RAID disks, maybe). Not that much different, given the different era?

Anyway, about Distributed, I just noticed "espeak", gonna add a routine into my RPC system so my "wiring" PI can "speak" for the others. Should be an interesting experiment.

p.p.s With Multiprocessing I can get all my cores idling together, all at the same time.

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davidcoton
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Re: Raspberry pi cluster

Tue Nov 08, 2016 8:44 pm

DavidS wrote: Do it with 16 Raspberry Pi 3B's and you may even be able to achieve real time Ray Tracing, maybe.
"Real time" ray tracing would need to compute the scene in the time it takes light to travel the longest path in the scene.
So it should be possible to do real time ray tracing of something like the solar system on a relatively low power processor.
But to trace the lighting in a room (windows, doors, ceiling and wall lights, decorative candles and at this time of year the Christmas tree lights) in real time -- forget it. :o :shock: :? :roll:
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Chazykins
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Re: Raspberry pi cluster

Tue Nov 08, 2016 10:16 pm

Thanks guys I've done some more research and a cluster is just a bit :lol: out of my price range. All though I have never heard of Ray tracing and that sounds fun to attempt :(


peterlite
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Re: Raspberry pi cluster

Wed Nov 09, 2016 12:26 am

Clusters can be used in several ways. A database could be segmented over four processors. A Web site could serve a different group of pages from each processor. Two together is enough to practice with a cluster or a grid processing array. I suggest starting with two.

peterlite
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Re: Raspberry pi cluster

Wed Nov 09, 2016 12:35 am

You could think of processor clusters as similar to RAID arrays. Two processors could share work a bit like RAID 1. Three processors could be grouped like RAID 5 with two processors sharing the workload and the third as a hot backup. I am currently adding a Zero to a Pi 3 with the Zero serving as a NAS for continuous rsync backup. The Zero is configured to be accessible as a "slightly warm" backup. :)

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DavidS
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Re: Raspberry pi cluster

Wed Nov 09, 2016 5:23 am

Chazykins wrote:Thanks guys I've done some more research and a cluster is just a bit :lol: out of my price range. All though I have never heard of Ray tracing and that sounds fun to attempt :(
For a good overview of raytracing see:
http://www.purplealienplanet.com/taxonomy/term/2

Raytracing is the easiest method of 3D rendering, it is also the most accurate and life like, though it is also the slowest method (hence why it is not yet used in games).

You could even play with Raytracing on a single RPi 3B, taking advantage of the 4 cores to speed things along. Quite fun programming excersise, and one of the standard second year CS projects in primary school (if you take that elective as a child, else in first year CS at university).
RPi = The best ARM based RISC OS computer around
More than 95% of posts made from RISC OS on RPi 1B/1B+ computers. Most of the rest from RISC OS on RPi 2B/3B/3B+ computers

Heater
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Re: Raspberry pi cluster

Wed Nov 09, 2016 5:49 am

What kind of Primary School do you mean?

For me Primary School was what you attended before going to High School at age 11. As far as I can tell most kids at that stage would not have the Maths chops to write a Ray Tracer. Of course in my day there were no computers in any school anyway.

Also we had no electives until much later. You did what you were told.

ejolson
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Re: Raspberry pi cluster

Thu Nov 10, 2016 12:38 am

Chazykins wrote:Thanks guys I've done some more research and a cluster is just a bit :lol: out of my price range. All though I have never heard of Ray tracing and that sounds fun to attempt :(
Clustering Raspberry Pi computers seldom results in something interesting from a performance point of view. However, clustering is a common technique used in both reliable and high performance computing that could be worth learning. Fortunately, designing software for a cluster of Pi zeros connected together using a USB hub is just as good as doing the same for a cluster of Pi 3B's using a proper network switch and quite similar to designing software that runs on real supercomputers.

Designing software that continues to run when one of the computers in the cluster is removed could be a valuable skill to have as well as knowing how to design software that runs twice as fast when twice as many computers are available. Such skills are particularly relevant for dynamically resizable computing clouds, which are becoming cheaper and more common as time goes on.

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DavidS
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Re: Raspberry pi cluster

Thu Nov 10, 2016 1:05 am

Heater wrote:What kind of Primary School do you mean?

For me Primary School was what you attended before going to High School at age 11. As far as I can tell most kids at that stage would not have the Maths chops to write a Ray Tracer. Of course in my day there were no computers in any school anyway.

Also we had no electives until much later. You did what you were told.
I do not know about other primary schools, though the private targeted education schools that I attended between ages 4 and 9 are what I know for primary school.

Therein each student was targeted to there fullest ability. That is the education focused on what each individual student was good at, and as such about half the courses were elective. And I had some great professors in primary school that I will never forget (and one head-master that I will never forget for different reasons ;) ).

I have heard rumours that other primary schools are different, though I am not sure what to believe on that.
RPi = The best ARM based RISC OS computer around
More than 95% of posts made from RISC OS on RPi 1B/1B+ computers. Most of the rest from RISC OS on RPi 2B/3B/3B+ computers

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