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Introduction

Questions

  • What is the Purpose of Formalism in Computer Science?

  • What is software development life cycle

  • There seem to be many concepts in this course. What do they mean?

Content

We start with a more theoretical introduction covering software and mindsets for software development.

Learning objectives of 'Introduction'

Learners can

  • Identify the main topics and objectives for the week's lessons.
  • Evaluate the importance of engaging with course content and identify strategies to maintain interest and motivation throughout the week.
Instructor notes

Prerequisites are:

The pre-requirements:

  • Learners know basic Git
  • Learners know basic Python
  • Learners have installed necessary tools

Teaching goals are:

  • Learners can can understand why a formalized development of software is important.

Lesson Plan:

  • Total 20 min
  • Theory 10
  • Discussions 10 min
TOC
  • What is software?
    • software concepts
    • types
    • outcome
      • correct, reusable, efficient, changable
  • Example
  • Software Development Life Cycle

Different types of Scientific software

  • analysis of data
    • statistics
    • figures
    • visualization
  • tools for process data
    • refining data (formatting)
    • bioinformatics
  • workflows
  • modelling (mimic the reality)
    • simulations time-varying behaviour of a system
    • mathematical models of relationships among variables in a system
  • decision assistance
  • Other

Discussion

What do you develop for?

Outcome of a Program

  • Correct
    • and flawless
  • Efficient
    • Utilize the computer system's resources
  • Reusable
    • Finished components
    • Lower development costs
    • Faster
    • Higher quality
    • packaging technology
  • Changeable
    • Maintenance cost
      • Fix errors, bugs
      • Adapt to new requirements
      • Independent modules
      • Encapsulation/information hiding

How to program?

Object oriented programming

  • Object-oriented (OO) programming is
    • a mindset of mimicking the real-world as:
    • entities (objects) that are different
    • or share attributeswith each-other (within a **class**)
    • info-hiding mindset...

Objects

Elevator objects

Class

classDiagram
  class Elevator{
    +string direction
    +int floor

    +goto_floor()
    +stop()
    + which_floor()
  }
Object orientation (OO) in some programming languages
  • OO (built-in classes)
    • C++
    • Java
    • Python
    • Julia
  • OO features
    • Fortran 2003-
    • MATLAB
    • Perl
    • PHP
  • OO object-based (but not class-based)
    • Javascript

Functional programming

  • More classical as it is more focused on the algorithms
  • Functions
  • Modules: a way to gather functions with similar functionality
  • Also to some extent info-hiding mindset

To sum up

  • At its simplest, functional programming uses immutable data to tell the program exactly what to do.
  • Object-oriented programming tells the program how to achieve results through objects altering the program's state.
  • Both paradigms can be used to create elegant code.

Modular coding

  • Modular coding breaks up the code in blocks that could be separate files.
  • Modularity could be within a program
  • ... but also for a workflow.
    • script describing order of runs with different programs
    • Ex. bash script for preparing input data, running Fortran programs and analysing output with python program.

Demo: WRF module and a workflow in 'runtime'

See also

Common problems

We want

  • Readability
  • Correct
  • Efficient
  • Reusable
  • Changeable
  • Can other people use your code?
  • Do you or anyone else understand your code at a later moment?
  • Does it work for all cases?
  • Is is easy to find when and where the code broke?
  • Is it easy to make changes in one part without ruin the rest of the program?
  • Does is use the resources efficiently?
  • Is is easy to use a part of the program in another program?
  • Can the program be run on different platforms
    • like Linux/Max/Windows,
    • like different hardware architectures (intel, amd, arm)

Discuss

  • Do you want to add something?
How can we make it easier to get good software and usefulness?

Software Development Life Cycle (SDLC)

  • We need a workflow in our programming projects!

Some common steps

  • Planning
    • Analysis and design
  • Development
    • Source control
    • Algorithms
    • In-code documentation
    • Optimization
      • Parallelism
    • Tests

  • Deployment and maintenance

    • Documentation
    • Reproducibility and sharing
    • Packaging and dependencies

  • ... and Iterations

  • Agile development

    • Division of tasks into short phases of work and frequent re-assessment and adaptation of plans.

Summary of Introduction

  • Now after the overview you are ready to dig deeper about the tools!

Keypoints

  • A program shall be or have content/components that is:

    • Correct
    • Efficient
    • Reusable
    • Changeable

  • Software development is both series of steps:

    1. Requirements
    2. Analysis and design
    3. Development
    4. Test
    5. Deployment and maintenance

  • ... and iteration of these

Learning objectives of 'Introduction'

Learners can

  • Identify the main topics and objectives for the week's lessons.
  • Evaluate the importance of engaging with course content and identify strategies to maintain interest and motivation throughout the week.