Let $f:\mathbb{R}\rightarrow \mathbb{R}$. Let $f_{\mathrm{max}}=\max_{x\in \mathbb R} f(x)$ and $f_{\mathrm{min}}=\min_{x\in \mathbb R} f(x)$. Define $r$ as the ratio of $f_{\mathrm{max}}$ to $f_{\mathrm{min}}$.
Intuitively, $r$ measures the "turbulence" of $f$. Is there a specific terminology for $r$?
