Essential Scientific Computing for Environmental Scientists

University of Liverpool

April 9th-10th 2024

09:30 - 17:00 BST

Instructors: Colin Sauze, Chris Wood

Helpers: Max Birkett, Tobias Ferreira, Ian Smith

General Information

The Carpentries project comprises the Software Carpentry, Data Carpentry, and Library Carpentry communities of Instructors, Trainers, Maintainers, helpers, and supporters who share a mission to teach foundational computational and data science skills to researchers.

Want to learn more and stay engaged with The Carpentries? Carpentries Clippings is The Carpentries' biweekly newsletter, where we share community news, community job postings, and more. Sign up to receive future editions and read our full archive: https://carpentries.org/newsletter/

Software Carpentry aims to help researchers get their work done in less time and with less pain by teaching them basic research computing skills. This hands-on workshop will cover basic concepts and tools, including program design, version control, data management, and task automation. Participants will be encouraged to help one another and to apply what they have learned to their own research problems.

For more information on what we teach and why, please see our paper "Best Practices for Scientific Computing".

This is a pilot workshop, testing out a lesson that is still under development. The lesson authors would appreciate any feedback you can give them about the lesson content and suggestions for how it could be further improved.

Who: The course is aimed at graduate students and other researchers. You don't need to have any previous knowledge of the tools that will be presented at the workshop.

Where: Seminar Room 4, Block J, Waterhouse Building, Brownlow Street, Liverpool, L69 3GL. Get directions with OpenStreetMap or Google Maps.

When: April 9th-10th 2024. Add to your Google Calendar.

Requirements: Participants must bring a laptop with a Mac, Linux, or Windows operating system (not a tablet, Chromebook, etc.) that they have administrative privileges on. They should have a few specific software packages installed (listed below).

Accessibility: We are committed to making this workshop accessible to everybody. For workshops at a physical location, the workshop organizers have checked that:

Materials will be provided in advance of the workshop and large-print handouts are available if needed by notifying the organizers in advance. If we can help making learning easier for you (e.g. sign-language interpreters, lactation facilities) please get in touch (using contact details below) and we will attempt to provide them.

Contact: Please email c.wood@epcc.ed.ac.uk for more information.

Roles: To learn more about the roles at the workshop (who will be doing what), refer to our Workshop FAQ.


Code of Conduct

Everyone who participates in Carpentries activities is required to conform to the Code of Conduct. This document also outlines how to report an incident if needed.


Collaborative Notes

We will use this collaborative document for chatting, taking notes, and sharing URLs and bits of code.


Surveys

Please be sure to complete these surveys before and after the workshop.

Pre-workshop Survey

Post-workshop Survey


Schedule

Day 1

Before Pre-workshop survey
09:30 Working with remote high performance computers
10:30 Morning break
11:00 Working with remote high performance computers (Continued)
12:00 Lunch break
13:00 Parallel processing with Numpy
14:30 Afternoon break
15:00 Parallel processing with Numpy (Continued)
16:00 Wrap-up
16:30 END

Day 2

09:00 Distributed data analysis with python<
10:30 Morning break
11:00 Distributed data analysis with python (Continued)
12:00 Lunch break
13:00 Advanced plotting
14:30 Afternoon break
15:00 Advanced plotting (Continued)
16:00 Wrap-up
16:30 Post-workshop Survey
16:40 END
The lesson taught in this workshop is being piloted and a precise schedule is yet to be established. The workshop will include regular breaks. Please [contact the workshop organisers](#contact) if you would like more information about the planned schedule.

Setup

To participate in a Software Carpentry workshop, you will need access to software as described below. In addition, you will need an up-to-date web browser.

We maintain a list of common issues that occur during installation as a reference for instructors that may be useful on the Configuration Problems and Solutions wiki page.

The Bash Shell

Bash is a commonly-used shell that gives you the power to do tasks more quickly.

  1. Download the Git for Windows installer.
  2. Run the installer and follow the steps below:
    1. Click on "Next" four times (two times if you've previously installed Git). You don't need to change anything in the Information, location, components, and start menu screens.
    2. From the dropdown menu, "Choosing the default editor used by Git", select "Use the Nano editor by default" (NOTE: you will need to scroll up to find it) and click on "Next".
    3. On the page that says "Adjusting the name of the initial branch in new repositories", ensure that "Let Git decide" is selected. This will ensure the highest level of compatibility for our lessons.
    4. Ensure that "Git from the command line and also from 3rd-party software" is selected and click on "Next". (If you don't do this Git Bash will not work properly, requiring you to remove the Git Bash installation, re-run the installer and to select the "Git from the command line and also from 3rd-party software" option.)
    5. Select "Use bundled OpenSSH".
    6. Ensure that "Use the native Windows Secure Channel Library" is selected and click on "Next".
    7. Ensure that "Checkout Windows-style, commit Unix-style line endings" is selected and click on "Next".
    8. Ensure that "Use Windows' default console window" is selected and click on "Next".
    9. Ensure that "Default (fast-forward or merge) is selected and click "Next"
    10. Ensure that "Git Credential Manager" is selected and click on "Next".
    11. Ensure that "Enable file system caching" is selected and click on "Next".
    12. Click on "Install".
    13. Click on "Finish" or "Next".
  3. If your "HOME" environment variable is not set (or you don't know what this is):
    1. Open command prompt (Open Start Menu then type cmd and press Enter)
    2. Type the following line into the command prompt window exactly as shown:

      setx HOME "%USERPROFILE%"

    3. Press Enter, you should see SUCCESS: Specified value was saved.
    4. Quit command prompt by typing exit then pressing Enter

This will provide you with both Git and Bash in the Git Bash program.

Video Tutorial

The default shell in Mac OS X Ventura and newer versions is Zsh, but Bash is available in all versions, so no need to install anything. You access Bash from the Terminal (found in /Applications/Utilities). See the Git installation video tutorial for an example on how to open the Terminal. You may want to keep Terminal in your dock for this workshop.

To see if your default shell is Bash type echo $SHELL in Terminal and press the Return key. If the message printed does not end with '/bash' then your default is something else, you can change your current shell to Bash by typing bash and then pressing Return. To check your current shell type echo $0 and press Return.

To change your default shell to Bash type chsh -s /bin/bash and press the Return key, then reboot for the change to take effect. To change your default back to Zsh, type chsh -s /bin/zsh, press the Return key and reboot. To check available shells, type cat /etc/shells.

Video Tutorial

The default shell is usually Bash and there is usually no need to install anything.

To see if your default shell is Bash type echo $SHELL in Terminal and press the Return key. If the message printed does not end with '/bash' then your default is something else, you can change your current shell to Bash by typing bash and then pressing Return. To check your current shell type echo $0 and press Return.

To change your default shell to Bash type chsh -s /bin/bash and press the Return key, then reboot for the change to take effect. To change your default back to Zsh, type chsh -s /bin/zsh, press the Return key and reboot. To check available shells, type cat /etc/shells.

Git

Git is a version control system that lets you track who made changes to what when and has options for easily updating a shared or public version of your code on github.com. You will need a supported web browser.

You will need an account at github.com for parts of the Git lesson. Basic GitHub accounts are free. We encourage you to create a GitHub account if you don't have one already. Please consider what personal information you'd like to reveal. For example, you may want to review these instructions for keeping your email address private provided at GitHub.

For macOS, install Git for Mac by downloading and running the most recent "mavericks" installer from this list. Because this installer is not signed by the developer, you may have to right click (control click) on the .pkg file, click Open, and click Open on the pop up window. After installing Git, there will not be anything in your /Applications folder, as Git is a command line program. For older versions of OS X (10.5-10.8) use the most recent available installer labelled "snow-leopard" available here.

Video Tutorial

If Git is not already available on your machine you can try to install it via your distro's package manager. For Debian/Ubuntu run sudo apt-get install git and for Fedora run sudo dnf install git.

Text Editor

When you're writing code, it's nice to have a text editor that is optimized for writing code, with features like automatic color-coding of key words. The default text editor on macOS and Linux is usually set to Vim, which is not famous for being intuitive. If you accidentally find yourself stuck in it, hit the Esc key, followed by :+Q+! (colon, lower-case 'q', exclamation mark), then hitting Return to return to the shell.

nano is a basic editor and the default that instructors use in the workshop. It is installed along with Git.

nano is a basic editor and the default that instructors use in the workshop. See the Git installation video tutorial for an example on how to open nano. It should be pre-installed.

Video Tutorial

nano is a basic editor and the default that instructors use in the workshop. It should be pre-installed.

Python

Python is a popular language for research computing, and great for general-purpose programming as well. Installing all of its research packages individually can be a bit difficult, so we recommend Anaconda, an all-in-one installer.

Regardless of how you choose to install it, please make sure you install Python version 3.x (e.g., 3.6 is fine).

We will teach Python using the Jupyter Notebook, a programming environment that runs in a web browser (Jupyter Notebook will be installed by Anaconda). For this to work you will need a reasonably up-to-date browser. The current versions of the Chrome, Safari and Firefox browsers are all supported (some older browsers, including Internet Explorer version 9 and below, are not).

  1. Open https://www.anaconda.com/products/individual#download-section with your web browser.
  2. Download the Anaconda for Windows installer with Python 3. (If you are not sure which version to choose, you probably want the 64-bit Graphical Installer Anaconda3-...-Windows-x86_64.exe)
  3. Install Python 3 by running the Anaconda Installer, using all of the defaults for installation except make sure to check Add Anaconda to my PATH environment variable.

Video Tutorial

  1. Open https://www.anaconda.com/products/individual#download-section with your web browser.
  2. Download the Anaconda Installer with Python 3 for macOS (you can either use the Graphical or the Command Line Installer).
  3. Install Python 3 by running the Anaconda Installer using all of the defaults for installation.

Video Tutorial

  1. Open https://www.anaconda.com/products/individual#download-section with your web browser.
  2. Download the Anaconda Installer with Python 3 for Linux.
    (The installation requires using the shell. If you aren't comfortable doing the installation yourself stop here and request help at the workshop.)
  3. Open a terminal window and navigate to the directory where the executable is downloaded (e.g., `cd ~/Downloads`).
  4. Type
    bash Anaconda3-
    and then press Tab to autocomplete the full file name. The name of file you just downloaded should appear.
  5. Press Enter (or Return depending on your keyboard). You will follow the text-only prompts. To move through the text, press Spacebar. Type yes and press enter to approve the license. Press Enter (or Return) to approve the default location for the files. Type yes and press Enter (or Return) to prepend Anaconda to your PATH (this makes the Anaconda distribution the default Python).
  6. Close the terminal window.