Function is_equal_eps 

pub fn is_equal_eps<T>(v1: T, v2: T, epsilon: T) -> bool
where
    T: Copy + PartialOrd + Sub<Output = T> + Add<Output = T> + Into<f64> + From<f64>,

Compare two floating-point values for approximate equality using relative comparison scaled by the smaller exponent. Port of C++ is_equal_eps.