linear programming software purchase vince like purchase copies xpress lp solver gas storage optimization model previously discussed purchase cplex trialing systems found worthwhile advantages xpress others find planner cplex best suited application see problem use different system strengths likely would use planner cplex future project systems available xpress particularly suited application handles special ordered sets efficient way representing storage ratchets integer search process able use extra information provided set rather using binary integer variables represent ratchets planner c interface cplex significant limitations permit access cplex features dash optimization made following offer software purchases made enron year 30 list price need make single purchase specific quantity licenses obtain discount 90 days full maintenance services provided purchase emosl utility provided cost xbsl system provided cost released weeks time gas storage optimization model would like purchase one development license hyper version modeller primal dual simplex mip search dlls emosl xbsl available list price 10 000 discounted price 7 000 two run time licenses list price total 8 000 discounted price 5 600 total cost 12 600 used usually security request system set purchase process going agree tom