  The necessary and sufficient conditions for minimization of the generalized
rate error for discriminating among $N$ pure qubit states are reformulated in
terms of Bloch vectors representing the states. For the direct optimization
problem an algorithmic solution to these conditions is indicated. A solution to
the inverse optimization problem is given. General results are widely
illustrated by particular cases of equiprobable states and $N=2,3,4$ pure qubit
states given with different prior probabilities.
