Radix Economy of Complex Bases

[SubZir0]

On the Wikipedia page for Radix Economy it shows how to find the economy (efficiency for data storage) of a positive real base like 2, e, 3, pi, etc but how would I find the economy of a complex or negative base?
http://en.wikipedia.org/wiki/Radix_economy

I want to find the economy of Donald Knuth's Quater-Imaginary base.
http://en.wikipedia.org/wiki/Quater-imaginary_base

 

[lurflurf]

The same way
digits required*number of digits possible

for Quater-Imaginary base there are 4 digit possibilities so
1223101 (base 2i)
has
E(2i,-35+40i)7*4=28

 

[SubZir0]

Thanks lurflurf, sorry about this but I don't understand how the Econ function would actually work with complex numbers. When I fill in the function I get a complex result:

log(-35+40)/log(2i) = 2.15.. -1.57..i

So basically I guess I'm asking how you find the length of a number in a complex base. With integer bases it works fine, but these complex bases seem more contrived..