Macro convert 

macro_rules! convert {
    ([ $($other:ty),+ ], $float:ty, $ctype:ident) => { ... };
}

This macro performs a conversion from any type that can cast into a float (either f32 or f64) and transforms it into a Either Complex or EComplex

If a type T is given, it is treated as a real only value. If the type (T, T) is given, it maps the struct’s fields directly to it