Function idwt_multilevel 

pub fn idwt_multilevel<T: SignalType>(
    result: &MultilevelDWTResult<T>,
    wavelet: &dyn Wavelet,
    boundary: BoundaryMode,
) -> Result<Signal<T>>

Perform multi-level 1D Inverse Discrete Wavelet Transform.

Reconstructs the input signal exactly to its original_length. Uses result.per_level_lengths to truncate each intermediate level back to its canonical length (necessary because M and L alone cannot distinguish N = 2M − L + 1 from N = 2M − L + 2).