Using i and j as variables in MATLAB

It is good practice to avoid i and j variables to prevent confusion about them being variables or the imaginary unit.

Personally, however, I use i and j as variables quite often as the index of short loops. To avoid problems in my own code, I follow another good practice regarding i and j: don’t use them to denote imaginary numbers. In fact, MATLAB’s own documentation states:

For speed and improved robustness, you can replace complex i and j by 1i.

So rather than avoiding two very commonly used variable names because of a potential conflict, I’m explicit about imaginary numbers. It also makes my code more clear. Anytime I see 1i, I know that it represents sqrt(-1) because it could not possibly be a variable.