Struct LPSquareFunction 

pub struct LPSquareFunction {
    pub signal: Vec<f64>,
}

Discrete Littlewood-Paley square function for a 1D signal of length N = 2^m.

Partitions the DFT spectrum into dyadic blocks [2ʲ, 2^{j+1}) and computes S(f)(i) = (Σⱼ |Δⱼf(i)|²)^{1/2} via inverse DFT of each block.

Fields

signal: Vec<f64>

The original signal.

Implementations

impl LPSquareFunction

pub fn new(signal: Vec<f64>) -> Self

Create from signal.

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

Compute the square function value at position i.

pub fn l2_norm_squared(&self) -> f64

L² norm of the square function (should ≈ L² norm of signal by LP inequality).