Function fde 

pub fn fde<S, E, F>(
    observations: &[Observation],
    options: &FdeOptions,
    solve: F,
) -> Result<FdeResult<S>, FdeError<E>>
where
    S: RaimSolution,
    F: FnMut(&[Observation]) -> Result<S, E>,

Fault detection and exclusion over a caller-supplied SPP solver.