# What makes a Supercomputer super?

Fugaku - the fastest supercomputer in the world. Image taken from: https://www.r-ccs.riken.jp/en/outreach/topics/20200513/

In my last blog post, I presented the Boltzmann-Nordheim equation and that Supercomputer can help us to solve this equation. This time, we have a look at the Supercomputer itself and how we can use it.

## Why do we need Supercomputers?

Before having a look at supercomputers, we might ask ourselves, for what kind of problems do we need them for? One major application of supercomputers is simulations. A current example for simulations is the COVID-19 Pandemic, where PRACE supports projects focussing on different aspects of the crises, as simulations of the spread of the disease or research to understand the virus itself.
Another example is the weather forecast, where supercomputers use the current weather to predict the upcoming weather. You will find many more examples, where supercomputers play an important role.

## Could my computer solve these problems?

For some of these problems, your personal computer might be able to compute a solution, but not to the precision that would satisfy the scientific needs and standards. Furthermore, your computer would just take too much time to finish the task. In the last weeks, I tried to run the code that simulates the Boltzmann-Nordheim equation on my computer at home – after an hour of waiting for a response, I just stopped the computation. Luckily, my supervisors gave me access to a more powerful computer, where I did not have to wait hours to get a result.

## But what makes it faster?

It is not just, that supercomputers have a faster CPU or a bigger RAM than your PC (the Fugaku, currently the fastest Supercomputer has 64PB RAM!). Their major strength is, that they have more CPUs than your PC. This way, you can more think about multiple Computers working together rather than a single big machine! In the video below we can see how we can benefit from having multiple CPUs.

## And how does that relate to your project?

In the video of the last post, I showed you, that I am focussing on a part of the equation, that describes the collision of the particles. My supervisor, Alexandre Mouton has developed a method that can further subdivide the collision term into pieces, such that they can be computed in parallel. My task is to get a good understanding of this method and to add it to the current state of the code.
In the last weeks, I had a look at his code and installed it onto my computer. Before editing the code, I need to understand it. With thousands of lines of codes, it was not easy to get into it. Luckily, I do not have to read and understand all of them as I do not have to adapt the whole project. Recently I started to implement the new method and planned what parts of the method I will focus on in the next weeks.
For now, I will head back to coding, but keep you up to date on every progress with the upcoming posts.

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###### 49 comments on “What makes a Supercomputer super?”
1. Comparing parallel computing with building LEGO – what a nice and visual explanation.

Which computer are you using during the summer of HPC?

P.s.: I am happy to see png2mesh being used 😉

• David Knapp says:

LEGO is awesome, HPC is awesome – it was a perfect match!

During the training week everyone of us was given access to the KAY supercomputer in Ireland.
Currently I have access to a cluster of the university of Lille.

2. Ria says:

I love the Lego visualization of the concept! Grogu is not just strong with force, but also strong with HPC!

• David Knapp says:

Grogu is awesome! Maybe I can use Grogu for Duck-debugging, too 😀

• Camilla says:

I haven’t known Grogu until now, but am about to become o fan of him …
🙃

3. Hannes says:

Never thought about the comparison of super computer and Lego. I love Lego and this blog gives me a perfect visualisation how a super computer works. I‘m looking forward to your next article!

• David Knapp says:

Thank you very much! I was looking for a very visual example of parallelization, and then this LEGO set came up in my mind! I am happy, that you like it!

4. Camilla says:

Very good explanation at all, thank you so much for it. And I also love the film, it’s such a great idea to explain supercomputers by building Grogu. Good job!

• David Knapp says:

Grogu is realy becoming the star of this Blog. Maybe I can use it for other examples!

5. Niklas S says:

The Lego force is strong in this one!
I really liked your explanation about the everyday use of supercomputers,like weather forecasts or modelling. Is it the same technique that the SETI programme is/was using?

• David Knapp says:

I totally agree there with you, it is amazing and surprising where supercomputers are used. With SETI you mean “Search for Extraterrestrial Intelligence”? I do not know much about the program, can you specify the technique you are referring to?

• Niklas S says:

Yes, search for aliens 😉 I think the programme initially used supercomputers to compute radio signals from outer space to search for intentionally made signals, like communication or from whatever generates signals that are not background noise. They later shifted the computing to a somewhat “cloud-based” approach, the SETI@home.
Maybe the outcome wasn’t as predicted and the cash flow has dried…

• David Knapp says:

That is indeed interesting, but I do not know the details about this project. But sure, this could be a task suited for supercomputers.

6. Christiane says:

Comparing Lego with a supercomputer is an excellent way to make the concept easier to understand. Very interesting topic. I’m looking forward to reading more of your articles!

• David Knapp says:

Thank you very much! As soon as I will have further progress, I will publish the next article!

7. Patrick says:

Haven’t thought a lot about supercomputers in the past. Crazy, what they can do! And even crazier, that often, we see it as completely normal!

Thanks for your very informative post and the super creative Video. Liked both very much! 🙂

• David Knapp says:

I am happy, that you liked the video and the post! The wide-ranging use of supercomputers is indeed impressive!

8. Aljoscha says:

I wish for the future, that every University in Germany get a supercomputer, so all students have the access to one and can work with one.

• David Knapp says:

Oh, that would be awesome! One goal of PRACE is to share the knowledge about high-performance computing in Europe!

9. Diana says:

Your comment is awaiting moderation. This is a preview; your comment will be visible after it has been approved.
Ein wirklich sehr interessanter Beitrag, ich bin begeistert…

• David Knapp says:

Vielen Dank für deinen Kommentar! Es freut mich, dass dir der Beitrag gefällt!

10. Simon Weßeling says:

Lego visualization, good and simple explanation.

• David Knapp says:

Thank you, that was the goal of the visualization!

11. Chris says:

Very nice visualization with the bricks. Makes it easier to understand the concept.

• David Knapp says:

Thank you very much! Grogu was a perfect example of the parallelization of programs.

12. Mona says:

Man sieht da ist ein Profi am Werk! Nicht nur beim Lego bauen (eine tolle Visualisierung, die man nicht vergessen wird!) – sondern auch die Erklärungen, die auch für für alle die sind, die sich noch nicht so mit Supercomputern auskennen. Super! 🙂

• David Knapp says:

Danke sehr für das tolle Lob! Genau das war die Absicht mit dem Video, dass es verständlich für jeden ist!

13. Veli says:

Your explanation using LEGO bricks is probably easy enough for a child to understand, even though the topic might sound scary at first, you made it so much better, interesting and less frightening. Great way to explain something!

PS: Grogu at least doubled the qualitiy of this.

Thanks for this cool video, keep it up.

• David Knapp says:

Thank you very much for you comment! It is always difficult to epxlain a complicated topic in a comperhensible way, but I think a nice visualization is always helpful. At least it always helped me a lot to visualize things during my studies! I am happy, that you liked it!

14. Andreas says:

Sehr informativ, sehr gut verständlich, vielen Dank dafür! Freue mich auf deine nächsten Posts …

• David Knapp says:

Vielen Dank! Schön, dass dir der Post gefällt!

15. Anki says:

Thank you very much for this nice explanation and great visualization.

• David Knapp says:

You`re welcome and thank you for your comment!

16. Michael says:

Nice visualisation and clever comparison. Very smart contribution.

• David Knapp says:

Thank you very much!

17. Arne says:

Good Job!

• David Knapp says:

Thank you!

18. Max says:

Nice visualization! I came dumb and leave now a little bit less dumb. #highlightofmyweek

• David Knapp says:

Thank you very much! I am happy, that you like the visualization and learned something about HPC! That is the goal of this blog!

19. Karen says:

I love the way you explain something so complex in an easy, visualized way!
It is very appealing, especially with Grogu in the picture 😀
Good luck with working through the code!

• David Knapp says:

Thank you very much! Grogu really is the star of this video!

20. Sina says:

Another great blog post! Can’t wait to read your next one and to hopefully watch another amazing video!

• David Knapp says:

Thank you very much!

21. Margrit says:

Thanks again for the great video. This visualiziation really helps to understand how supercomputers work compared to the serial ones.

• David Knapp says:

Thank you very much! I am happy, that you are enjoying the visualization!

22. Philipp says:

Very good visualization! Thank you for this very cool blog post!

• David Knapp says:

Thank you very much! It was a lot of fun to make it!

23. Henning says:

I – indeed – understand more then Lego 👍

• David Knapp says:

That is, what I was aiming for!

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