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Graphics

Learning objectives

  • Make a first scatter plot
  • Rehearse running a script that uses an import
  • Rehearse that graphics need X-forwarding
For teachers

Teaching goals are:

  • Learners hear about matplotlib
  • Learners may find out again that X-forwarding is important
  • Learners again have gotten 'stuff to work'

Lesson plan:

  • 5 mins: prior knowledge
  • 5 mins: presentation
  • 15 mins: challenge
  • 5 mins: feedback

Prior:

  • What is meant with a plotting library?
  • What is meant with a plotting package/module?
  • Can you name a Python plotting package?

Overview

Sometimes one wants to make a plot, such like a scatterplot or barchart. Matplotlib is a popular Python package to make plots. Here we experience how easy/hard it is to use Matplotlib on Rackham.

flowchart TD
    python[[Python]]

    %% Give a white background to all nodes, instead of a transparent one
    classDef node fill:#fff,color:#000,stroke:#000

    subgraph sub_programming_language[Programming language]
      interpreted_language[Interpreted language]
      programming_language[Programming language]
      scripting_language[Scripting language]
      interpreter[Interpreter]
      scripts[Scripts]
      text_files[Text files]
    end
    style sub_programming_language fill:#ccf,color:#000,stroke:#fcc

    subgraph sub_programming_terms[Programming terms]
      user_input[User input]
      file_io[File I/O]
      command_line_arguments[Command-line arguments]
      variables[Variables]
      operators[Operators]
      %% functions[Functions]
      python_packages[Python packages]
      graphics[Graphics]
    end 
    style sub_programming_terms fill:#cfc,color:#000,stroke:#fcc

    subgraph sub_uppmax[UPPMAX]
      uppmax[UPPMAX]
      uppmax_modules[UPPMAX modules]
      uppmax_clusters[UPPMAX clusters]
      text_editors[Text editors]
      x_forwarding[X-forwarding]
      remote_desktop[Remote desktop]
    end
    style sub_uppmax fill:#fcc,color:#000,stroke:#fcc

    python --> |is a| programming_language
    python --> |is a| interpreted_language
    python --> |is a| scripting_language

    programming_language --> |uses| text_files
    interpreted_language --> |has a| interpreter
    scripting_language --> |is|interpreted_language
    scripting_language --> |runs| scripts
    scripts --> |are| text_files
    scripts --> |can use| command_line_arguments

    python --> |has| python_packages
    python --> |has| variables
    %%python --> |has| functions
    python --> |has| operators
    %%functions --> |use| variables
    operators --> |work on| variables
    python_packages --> |allow| graphics
    python_packages --> |allow to use| user_input
    python_packages --> |allow to do| file_io
    python_packages --> |allow to use| command_line_arguments

    uppmax --> |has| uppmax_clusters
    uppmax_clusters --> |have| uppmax_modules
    uppmax_clusters --> |have| text_editors
    uppmax_clusters --> |allow| x_forwarding
    uppmax_clusters --> |has| remote_desktop
    uppmax_modules --> |allow the use of| python_packages
    uppmax_modules --> |allow the use of| interpreter

    text_editors --> |work on|text_files
    x_forwarding --> |allows|graphics
    remote_desktop --> |allows|graphics


    variables ~~~ uppmax

Exercises

See the exercise procedure here.

Exercise 1: Use matplotlib to show a plot

Learning objectives

  • Make a first scatter plot
  • Rehearse running a script that uses an import
  • Rehearse that graphics need X-forwarding

Read matplotlib's 'Pyplot tutorial' here.

Copy-paste the first script on that page to a script and get it to work. Do you expect this to be easy?