Coding mathematical algorithms - should I use variables in the book or more descriptive ones?

Question

I'm maintaining code for a mathematical algorithm that came from a book, with references in the comments. Is it better to have variable names that are descriptive of what the variables represent, or should the variables match what is in the book?

For a simple example, I may see this code, which reflects the variable in the book.

A_c = v*v/r

I could rewrite it as

centripetal_acceleration = velocity*velocity/radius

The advantage of the latter is that anyone looking at the code could understand it. However, the advantage of the former is that it is easier to compare the code with what is in the book. I may do this in order to double check the implementation of the algorithms, or I may want to add additional calculations.

Perhaps I am over-thinking this, and should simply use comments to describe what the variables are. I tend to favor self-documenting code however (use descriptive variable names instead of adding comments to describe what they are), but maybe this is a case where comments would be very helpful.

I know this question can be subjective, but I wondered if anyone had any guiding principles in order to make a decision, or had links to guidelines for coding math algorithms.

Answer 1

I would prefer to use the more descriptive variable names. You can't guarantee everyone that is going to look at the code has access to "the book". You may leave and take your copy, it may go out of print, etc. In my opinion it's better to be descriptive.

We use a lot of mathematical reference books in our work, and we reference them in comments, but we rarely use the same mathematically abbreviated variable names.