Function compare_methods 

pub fn compare_methods(
    smiles: &str,
    elements: &[u8],
    positions: &[[f64; 3]],
    allow_experimental_eht: bool,
) -> MethodComparisonResult

Compare multiple supported methods on the same geometry/system.

This workflow executes available methods independently and returns per-method status, confidence metadata, warnings, limitations, and compact outputs.