Function follow 

pub fn follow<C: Condition + ?Sized>(
    condition: &C,
    start: &[f64],
    options: Marching,
    tol: Tolerances,
) -> OgeomResult<Walked>

Follow a condition’s curve both ways from a starting point.

Forwards first; if that closes, the curve is a loop and there is nothing behind. Otherwise the backward half is walked: if that closes, it is the loop, and otherwise the two are joined.

Errors

OgeomError::Construction if the settings are unusable, or the start does not have the condition’s own number of unknowns.