[tor-talk] How to select the path using the weights?

[Lu Yu]

I know how these weights (Wgg, Wgm .....) are calculated. But then what?

How to choose the path using the weights? My understanding is to 
calculate the weighted sum of the bandwidth of each possible circuits 
(Isn't the computation too much?). And then choose the path with the 
maximum bandwidth (Then every one would choose the same path)? Or using 
the bandwidth to build some probability distribution?

I am totally confused.