Integer and Goal Programming
Linear Programming Extensions • Integer Programming • Linear, integer solutions
• Goal Programming • Linear, multiple objectives
• Nonlinear Programming • Nonlinear objective and/or constraints
Three Types of Integer Programming Problems 1. Pure integer programming problems •
All variables integer.
1. Mixed-integer programming problems •
Some variables integer.
1. Zero-one integer programming problems •
All variables either 0 or 1.
Integer Programming Techniques • Gomory’s Cutting Plane Method • Branch and Bound Method
Goal Programming Versus Linear Programming • Multiple Goals (instead of one goal) • Deviational Variables Minimized (instead of maximizing profit or minimizing cost of LP) • “Satisficing” (instead of optimizing) • Deviational Variables are Real (and replace slack variables)
Harrison Electric Company Goal Programming Original Problem Max : 7 X 1 + 6 X 2 Subject to:: 2 X 1 + 3 X 2 ≤ 12 6 X 1 + 5 X 2 ≤ 30 Problem with goal of Profit = 30 − Min : d1 Subject to::
7 X1 + 6 X 2 + d1− −d1+ = 30 2 X1 + 3 X 2 ≤ 12 6 X1 + 5 X 2 ≤ 30
Initial Goal Programming Tableau Cj
0
0 P1 P2 0 P4 0
0 P3 0
Pivot Column
Solution x1 x2 d1- d2- d3- d4- d1+ d2+ d3+ d4+ Quantity Mix P1
d1-
7
6
1
0
0
0 -1 0
0
0
30
P2
d2-
2
3
0
1
0
0
0 -1 0
0
12
0
d3-
6
5
0
0
1
0
0
0 -1 0
30
P4
d4-
0
1
0
0
0
1
0
0
0 -1
7
Zj 0 1 0 { P4 Cj - Zj 0 -1 0
0
0
1
0
0
0 -1
7
0
0
0
0
0
0 -1
0 { Zj P3 Cj - Zj 0 Zj 2 { P2 Cj - Zj -2
0
0
0
0
0
0
0
0
0
0 3
0 0 0 1
0 0
0 0
0 0 1 0 -1 0
0 0
0
0
0
0
1
0
0
1
0
0
0 -1 0
0
0
3
0
0
0
0
0
0
0
-3 0
7 6 { Zj P1 Cj - Zj -7 -6
1
0
0 1 2
Second Goal Programming Tableau Cj
0
0 P1 P2 0 P4 0
0 P3 0
Pivot Column
Solution x x d - d - d - d - d + d + d + d + 1 2 1 2 3 4 1 2 3 4 Quantity Mix P1
x1
1 6/7 1/7 0
0
0 -1/7 0
0
0
30/7
P2
d2-
0 9/7 -2/7 1
0
0 +2/7 -1 0
0
24/7
0
d3-
0 -1/7 -6/7 0
1
0 6/7 0 -1 0
30/7
P4
d4-
0
1
0
0
0
1
0
0
0 -1
7
Zj 0 1 0 { P4 Cj - Zj 0 -1 0
0
0
1
0
0
0 -1
7
0
0
0
0
0
0 +1
0 { Zj P3 Cj - Zj 0
0
0
0
0
0
0
0
0
0 0
0
0
0
0
0
1
0
Z 0 9/7 -2/7 1 P2 { j Cj - Zj 0 -9/7 +2/7 0
0
0 2/7 -1 0
0 24/7
0
0 -2/7 +1 0
0
0 { Zj P1 Cj - Zj 0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
1
0
0
0
0
0
Final Solution to Harrison Electric’s Goal Programming Cj
0
0 P1 P2 0 P4 0
0 P3 0
Solution x x d - d - d - d - d + d + d + d + 1 2 1 2 3 4 1 2 3 4 Quantity Mix P1
d2+
8/5 0
0 -1 3/5 0
0
1 -3/5 0
6
P2
x2
6/5 1
0
0 1/5 0
0
0 -1/5 0
6
0
d1+
1/5 0 -1 0 6/5 0
1
0 -6/5 0
6
P4
d4+
-6/5 0
0
0 -1/5 1
0
0 1/5 -1
1
Zj -6/5 0 { P4 Cj - Zj 6/5 0
0
0 -1/5 1
0
0 1/5 -1
1
0
0 1/5 0
0
0 -1/5 -1
0
0
0
0
0
0
0
0
0 0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0 { Zj P3 Cj - Zj 0 Zj 0 { P2 Cj - Zj 0
0 0
0
0
1
0
0
0
0
0
0
0 { Zj P1 Cj - Zj 0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0 0 0