So, I'm trying to learn Rust. And in thinking about the ontological status of
mathematical representations of waves (https://arxiv.org/abs/2101.10873), I
figured I'd validate Euler's identity:
fn main() {
let e = num::complex::Complex::new(std::f32::consts::E,0.);
let e2ip = e.powc(num::complex::Complex::new(0.,std::f32::consts::PI));
let i = num::complex::Complex::new(0.,1.);
println!("ln(e^iπ) = {}",e2ip.ln());
println!("ln(-1) = {}", i.powi(2).ln());
}
$ cargo run
ln(e^iπ) = 0+3.1415925i
ln(-1) = 0+3.141592653589793i
I don't have any idea if that's a reasonable way to do that, since I'm ignorant
of Rust. But it's interesting to contrast it with R and Sage:
$ Rscript -e "log(exp(1)^((0+1i)*pi));log((0+1i)^2)"
[1] 0+3.141593i
[1] 0+3.141593i
sage: numerical_approx(ln(e^(i*pi)));numerical_approx(ln(i^2))
3.14159265358979*I
3.14159265358979*I
The precision difference between the 2 results in Rust is interesting. It's the
same if I use powf() instead of powi(). Any clues? Or should I simply RTFM?
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