modfixed_base;modvariable_base;pubusefixed_base::*;pubusevariable_base::*;/// The result of this function is only approximately `ln(a)`
/// [`Explanation of usage`]
////// [`Explanation of usage`]: https://github.com/scipr-lab/zexe/issues/79#issue-556220473
fnln_without_floats(a:usize)->usize{// log2(a) * ln(2)
(ark_std::log2(a)*69/100)asusize}