/* 
 * Discrete Fourier transform (Rust)
 * by Project Nayuki, 2017. Public domain.
 * https://www.nayuki.io/page/how-to-implement-the-discrete-fourier-transform
 */


fn compute_dft(inreal: &[f64], inimag: &[f64], outreal: &mut [f64], outimag: &mut [f64]) {
	let n: usize = inreal.len();
	for k in 0 .. n {  // For each output element
		let mut sumreal: f64 = 0.0;
		let mut sumimag: f64 = 0.0;
		for t in 0 .. n {  // For each input element
			let angle: f64 = 2.0 * std::f64::consts::PI
				* (t as f64) * (k as f64) / (n as f64);
			sumreal +=  inreal[t] * angle.cos() + inimag[t] * angle.sin();
			sumimag += -inreal[t] * angle.sin() + inimag[t] * angle.cos();
		}
		outreal[k] = sumreal;
		outimag[k] = sumimag;
	}
}