Function fftfreq 

pub fn fftfreq(n: usize, d: f64) -> FFTResult<Vec<f64>>

Return the Discrete Fourier Transform sample frequencies.

Arguments

• n - Number of samples in the signal
• d - Sample spacing (inverse of the sampling rate). Defaults to 1.0.

Returns

A vector of length n containing the sample frequencies.

Examples

use scirs2_fft::fftfreq;

let freq = fftfreq(8, 0.1).unwrap();
// frequencies for n=8, sample spacing of 0.1
// [0.0, 1.25, 2.5, 3.75, -5.0, -3.75, -2.5, -1.25]
assert!((freq[0] - 0.0).abs() < 1e-10);
assert!((freq[4] - (-5.0)).abs() < 1e-10);