OPTION DISPWIDTH=15

SET INGREDTS NAMES OF THE AVAILABLE FEED INGREDIENTS
/CORN the proportion of corn used in one pound of feed
HAY the proportion of hay used in one pound of feed
SOYBEAN the proportion of soybeans used in one pound of feed
WHEAT the proportion of wheat in one pound of feed
OATS the proportion of oats in one pound of feed
RICE the proportion of rice in one pound of feed
/
INGREDT(INGREDTS) SUBSET OF THE AVAILABLE FEED INGREDIENTS
/ CORN the proportion of corn used in the small model
HAY the proportion of hay used in the small model
SOYBEAN the proportion of soybeans used in the small model
/

  NUTRIENTs            NUTRIENT REQUIREMENT CATEGORIES
  /Protein   each pound of feed has a minimum protien requirement
   VitaminA  each pound of feed has a minimum Vitamin A requirement
   VitaminC  each pound of feed has a minimum Vitamin C requirement
   VitaminD  each pound of feed has a minimum Vitamin D requirement
  /

  NUTRIENT(NUTRIENTs)  NUTRIENT REQUIREMENT CATEGORIES
  / Protein   protein is used in the small model
    VitaminA  vitamin A is used in the small model
  /  ;

INGREDT(INGREDTS)=YES;
NUTRIENT(NUTRIENTs)=YES;

PARAMETER INGREDCOST(INGREDTS) FEED INGREDIENT COSTS PER POUND PURCHASED
/CORN 3.0
HAY 4.0
SOYBEAN 5.0
WHEAT 2.0
OATS 5.4
RICE 3.0
/;

PARAMETER NUTREQUIRE(NUTRIENTS) NUTRIENT REQUIREMENTS
/
Protein 0.05
VitaminA 0.09
VitaminC 0.28
VitaminD 1200 /;

*SCALAR UnitLimit /1/;

TABLE CONTENT(NUTRIENTS, INGREDTS) NUTRIENT CONTENTS PER POUND OF FEED INGREDIENT
CORN HAY SOYBEAN WHEAT OATS RICE
Protein 0.01 0.04 0.07 0.025 0.04 0.02
VitaminA 0.02 0.14 0.1 0.07 0.09 0.06
VitaminC 0.15 0.05 0.2 0.25 0.16 0.12
VitaminD 600 1000 700 1600 1500 2000
;

POSITIVE VARIABLES
FEEDUSE(INGREDTS) AMOUNT OF EACH INGREDIENT USED IN MIXING FEED;

VARIABLES
COST PER LB COST OF THE MIXED FEED;
EQUATIONS
OBJT OBJECTIVE FUNCTION ( TOTAL COST OF THE FEED )
MINLimit(NUTRIENTS) MINIMUM LIMITS ON EACH NUTRIENT IN THE BLENDED FEED
WEIGHT REQUIREMENT THAT EXACTLY ONE LB OF FEED BE PRODUCED;

OBJT..
COST =E= SUM(INGREDT, -INGREDCOST(INGREDT) * FEEDUSE(INGREDT));

MINLimit(NUTRIENT)..
SUM(INGREDT, CONTENT(NUTRIENT, INGREDT) * FEEDUSE(INGREDT))
=G= NUTREQUIRE(NUTRIENT);

WEIGHT..
SUM(INGREDT, FEEDUSE(INGREDT)) =E= 1 ;

MODEL FEEDING /ALL/;
SOLVE FEEDING USING LP MINIMIZING COST;