# Geocomputing coffee
###### tags: `SwissGeocomputingCentre` `computing-coffee`

:::info
:bulb: **What is this geocomputing coffee about?**
- informal get-together over lunchtime with people interested in -- or curious about -- the geocomputing thematic
- exchange and learn about computational-related topics
- share your latest advances or discuss technical issues
:::

### :question: What would you like to discuss?

- create a small package and make it available on GitHub
- in Python
- in Julia
- Julia in the geosciences
- differentiable programming
- Python HPC workflow
- Python best practice

## Upcoming Meeting

:::warning
### :writing_hand: Register here
**If you are planning to attend** please add your name & email to the following list _(first you need to select the edit mode in the upper left corner of the window)_:

Ludovic Räss, [e-mail]
Ayoub Fatihi, [e-mail] 
Jingyan Yu, [e-mail]
William Halter, [e-mail]

:::

:::danger
### Optimal meeting day/time
- Next meeting
- Thursday 9.11 at 10h30 - 11h30 | xxxxxx
- Thursday 9.11 at 12h15 - 13h15 | xxxxxx
- Thursday 16.11 at 10h30 - 11h30 | xxx
- Thursday 16.11 at 12h00 - 13h00 | xxxx
- Preferred meeting time
- Thursdays at 10h30 - 11h30 | xxxxxx
- Thursdays at 12h15 - 13h15 | xxxxxxx
- Other suggestion
- else?
:::

> **TOPIC**: Git, GitHub, Remote-SSH via VS Code

### :computer: Hands-on

:::info
:bulb: Ideally, bring your laptop to follow along the GitHub demo in order to apply it live, or later, to your personal needs. If interested, having already a GitHub account could be a good starting point.
:::

- Cover the material of the following tutorial https://github.com/Unil-SGC/geocomputing-coffee/tree/main/1-git-demo in slow motion
- demo about the basics of using git, GitHub, and Julia
- syncing local and remote repos using git
- running interactively on Curnagl GPU node

---
_do not modify anything below this here_

## Meeting 26.10.23

:::warning
### :writing_hand: Register here
**If you are planning to attend** please add your name & email to the following list _(first you need to select the edit mode in the upper left corner of the window)_:

Ludovic Räss, [e-mail]
Marj Tonini, [e-mail]
Tom Beucler, [e-mail]
Beatriz Quintal, [e-mail]
François Bavaud, [e-mail]
Haokun Liu, [e-mail]
William Halter, [e-mail]
Stefan Schmalholz, [e-mail]
Jingyan Yu, [e-mail]
Edith Sotelo, [e-mail]
Ben Klein, [e-mail]
James Irving, [e-mail]
Marc-Henri Derron, [e-mail]
Milton Gomez, [e-mail]
Mattia Mazzucchelli, [e-mail]
Anindita Samsu, [e-mail]
Ayoub Fatihi, [e-mail]
Ian Delaney, [e-mail]
Luca Bütikofer, [e-mail]
Flavio Calvo, [e-mail]
Alessio Poloni, [e-mail]
Emmanuel Jeanvoine, [e-mail]
Pau Wiersma, [e-mail]
Fuxiao Jiang, [e-mail]
Liudmila Khakimova, [e-mail]
Zenan Huo, [e-mail]
György Hetényi, [e-mail]
Alannah Brett, [e-mail]
Antonin Chalé, [e-mail]
Christian Kaiser, [e-mail]

:::

> **TOPIC**: Introducing the **geocomputing coffee** in FGSE

:::info
- Meeting time **12h10 - 13h15**
- Room **GEO 2138**
:::

### Schedule

| Time | Column 2 | Column 3 |
| -------- | -------- | -------- |
| 12h10 - 12h30 | [Welcome](#Welcome) - SGC (+ DCSR) intro | Marj, Ludovic, Flavio |
| 12h30 - 12h45 | Grabbing Lunch | |
| 12h45 - 13h20 | [Hands-on](#-Hands-on) - git/GitHub/Julia | Ludovic |
| 13h20 - 13h25 | Wrapping-up, what's up next? | Marj, Ludovic |

### Welcome
As a first get-together, the goal of this meeting is to:
- (Re)-introduce briefly the Swiss Geocomputing Centre (SGC)
- Website https://unil-sgc.github.io
- GitHub organisation https://github.com/Unil-SGC
- Discord chat server
- Introduce the activities we plan to offer within the SGC **geocomputing coffee**
- Provide a hands-on about version control and reproducible science using good-practices and tools for software carpentry.

### :computer: Hands-on

:::info
:bulb: Ideally, bring your laptop to follow along the GitHub demo in order to apply it live, or later, to your personal needs. If interested, having already a GitHub account could be a good starting point.
:::

- demo about the basics of using git, GitHub, and Julia
- syncing local and remote repos using git
- running interactively on Curnagl GPU node

#### Pre-requisite
1. Install VS Code (free editor): https://code.visualstudio.com
2. Install [Julia](https://julialang.org) (open source): [download](https://julialang.org/downloads/) | [juliaup](https://github.com/JuliaLang/juliaup)
3. Install VS Code extensions: [Julia extension](https://code.visualstudio.com/docs/languages/julia#_getting-started) | [Remote-SSH extension](https://code.visualstudio.com/blogs/2019/07/25/remote-ssh#_connect-using-remote-ssh)
4. Create a GitHub account: https://github.com
5. Have access to Curnagl
6. Set-up password-less ssh; see [Connexion with a key](https://wiki.unil.ch/ci/books/high-performance-computing-hpc/page/ssh-connection-to-dcsr-cluster)
8. Add an entry to the hostfile as

  Host curnagl
    HostName curnagl.dcsr.unil.ch
    User <username>
    IdentityFile ~/.ssh/id_ed25519

#### Do it yourself
1. On github.com
- Create a repository on GitHub
2. On your local computer
- Clone it locally
- Launch Julia from VS Code
- Add a memcopy script `A = B + s * C`:
- using broadcasting
- using loops
- :point_right: you can find the script [:pencil: here](https://gist.github.com/luraess/7e7410ac4113b9fe9bb951510d0baf76)
- Report performance
- Commit and push the script (from your local computer)
3. On a remote server (here `curnagl`)
- Log into Curnagl and request an interactive node

      Sinteractive

- Load the Julia and CUDA modules

      module load gcc/10.4.0
      module load julia
      module load cuda

- navigate to your scratch space `cd /scratch/<username>`
- git clone the git repository you created and populated previously

      git clone ...

- Create a new branch (here named `gpu-test`)

      git checkout -b gpu-test

- Add CUDA package and a GPU kernel to perform memory copy:

      function memcopy_gp!(A, B, C, s)
          ix = (blockIdx().x-1) * blockDim().x + threadIdx().x
          iy = (blockIdx().y-1) * blockDim().y + threadIdx().y
          A[ix, iy] = B[ix, iy] + s * C[ix, iy]
          return
      end
      
      CUDA.@sync @cuda blocks=$blocks threads=$threads memcopy_gp!($A, $B, $C, $s)

- Add remaining details to make it work
- Test it :rocket:
- Commit and push on using VS Code git capabilities
4. Verify that the changes synced on github.com and pull them locally