Function forward_jacobian 

pub fn forward_jacobian<F, Func>(
    f: Func,
    x: ArrayView1<'_, F>,
) -> IntegrateResult<Array2<F>>
where
    F: IntegrateFloat,
    Func: Fn(&[Dual<F>]) -> Vec<Dual<F>>,

Compute Jacobian using forward mode AD (convenience function)