Mixed-comparator construction function
q(w_j,C_j,E_j) = (C_mix,E_mix)
Maps the treatment shares and expected results of current-care options to a weighted mixed comparator.
Weighted mixed-comparator cost
C_mix = sum_(j=1)^J (w_j * C_j)
Weighted mixed-comparator outcome
E_mix = sum_(j=1)^J (w_j * E_j)