[bugfix][complex] cast 1.0 into field_type in 1.0/x expressions
The expression 1.0/x, where x is a std::complex lead to a compile error. This is fixed by casting 1.0 explicit to the used field_type.
The expression 1.0/x, where x is a std::complex lead to a compile error. This is fixed by casting 1.0 explicit to the used field_type.