Function newton_raphson 

pub fn newton_raphson<F, D>(
    f: F,
    derivative: D,
    initial: f64,
    options: RootOptions,
) -> Result<f64, RootError>
where
    F: Fn(f64) -> f64,
    D: Fn(f64) -> f64,

Finds a root with Newton-Raphson iteration.

This is an approximate iterative solver, not an exact equation helper. The tolerance must be finite and positive. Non-finite values and approximately zero derivatives return explicit errors.

Errors

Returns RootError::InvalidTolerance when the tolerance is not finite and positive; RootError::NonFiniteValue when the initial value, a function evaluation, a derivative evaluation, or the next iterate is non-finite; RootError::ZeroDerivative when the derivative is approximately zero; and RootError::MaxIterationsReached when the iteration budget is exhausted without convergence.