set prd := nuts bolts washers;
set raw := iron nickel;

param T := 4;
param max_prd := 123.7;

param units :     nuts    bolts   washers  :=
        iron      .79      .83      .92
        nickel    .21      .17      .08    ;

param profit :      1       2       3       4    :=
        nuts       1.73    1.8     1.6     2.2
        bolts      1.82    1.9     1.7     2.5
        washers    1.05    1.1      .95    1.33  ;

param :         init_stock    cost    value  :=
        iron       35.8       .03      .02
        nickel     7.32       .025    -.01   ;