where w E , w p , n val , E true,i , E pred,i , p true,i , and p pred,i represent bulk modulus weight, proxy weight, number of validation points, DFT-calculated bulk modulus of the i-th validation point, predicted bulk modulus of the i-th validation point, true proxy property of the i-th validation point, and predicted proxy property of the i-th validation point, respectively. We use w E = 1 and w p = 1.