The difference is that in Matlab, 1 + j is valid as a complex literal and equal to 1 + 1j. In Python it is never valid to write j as an implicit 1j, so this par

The difference is that in Matlab, 1 + j is valid as a complex literal and equal to 1 + 1j. In Python it is never valid to write j as an implicit 1j, so this particular bug (a correctly working function stops working because you've put a new name into scope) can't arise. The use of j is common in electrical engineering, where i denotes current.