Struct FourierSpectralMethod 

pub struct FourierSpectralMethod {
    pub N: usize,
    pub domain_length: f64,
}

Fourier spectral method on a periodic domain.

Fields

N: usize

Number of modes (collocation points).

domain_length: f64

Length of the periodic domain.

Implementations

impl FourierSpectralMethod

pub fn new(N: usize, domain_length: f64) -> Self

Create a new FourierSpectralMethod.

pub fn spectral_differentiation_matrix(&self) -> Vec<Vec<f64>>

Build the N×N spectral differentiation matrix for the periodic grid.

D_{jk} = (π/L) · (-1)^{j-k} / tan(π(j-k)/N) (j ≠ k), D_{jj} = 0.

pub fn fft_solve_poisson(&self, rhs: &[f64]) -> Vec<f64>

Solve −u’’ = f on [0, L] with periodic BC using FFT.

Returns the solution u at the N evenly-spaced collocation points, with the mean value set to zero.