# Data Envelopment Analysis following the formulation given
# in Williams, "Model Building in Mathematical Programming".
#
set DMU;
set Input;
set Output;

param ipar {DMU, Input};
param opar {DMU, Output};
param k symbolic in DMU;

var w >= 1;
var x {DMU} >= 0;

maximize z: w;

s.t. inputs  {i in Input}:  sum {j in DMU} ipar[j,i]*x[j] <= ipar[k,i];
s.t. outputs {i in Output}: sum {j in DMU} opar[j,i]*x[j] >= opar[k,i]*w;