Question

What’s the best way to calculate a geometric progression in Ruby?

Are there any built-in methods available?

Should I use some math gem?

Or should I implement my own small function?

Answer 1

I don’t think the task is complicated enough to expect an external library.

I feel that this might be more efficient than ranksrejoined’s answer:

def geo_prog a, r, n
    (n - 1).times.inject([a]){|a| a << a.last * r}
end