Coding Tips

Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live. John Woods

A few tips for writing code, especially that kind doing computationally costly simulations.

<note tip>None of these points is obligatory, neither is the list comprehensive. But bear in mind that its the result of personal (practical) experience (of several people) over quite some time.</note>

• Use meaningful filenames.
  • Develop a sensible directory hierarchy for your codes and projects.
  • Where possible, write reusable code and store it in a separate directory that gets added to the Matlab path.
• Use functions rather than scripts, whereever possible.
• Try to avoid for loops whereever possible.
  • Matlab offers you a broad range of matrix manipulation methods that are much faster in Matlab than for loops.
• Document your code carefully.
  • Note: Even you will struggle to understand what your code does, if you look at it after two months.
  • Possibly, others want to make use of your code, at least try to understand what you did, and if necessary, adapt it for their needs.
• Add a description of what the file does at the top of all your files.
  • Add references to papers if relevant.
• Add a history bit at the top of all your files (below the general description).
  • At least, the date of the last modification.
  • If you modify something, add a short note what has changed (and why).
• Use sensible names for variables.
  • It doesn't matter if they are long.
  • Where applicable, add comment lines telling what these variables are.
• Add comment lines in the source code describing shortly what the following lines do.

If you plan to add your code or at least parts of it to a thesis:

• Beware of the line lenghts
  • Display a vertical line for the maximum line length in your editor¹⁾
  • Break long lines using …

• Save results to a file.
  • Easiest: Save as Matlab file (“.mat”).
  • Use a proper name that allows you to easily recognise the file contents.
  • Save all the parameters you used for the calculations, and that are important to repeat it.
  • Perhaps also save a string with a description in it.
• Save the graphics files.
  • Save as Matlab fig file (allows later modifications)
  • Save as EPS or PDF file (allows including in reports)
    • (Normally) a vector format, therefore allows scaling
• Write short summaries.
  • Whereever possible and suitable, sum up your results for a (sub-)project before moving on to the next problem.