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Transportation Method. Lecture 20 By Dr. Arshad Zaheer. RECAP. T ransportation model (Minimization) Illustration (Demand < Supply) Optimal Solution Modi Method. Maximization Total Demand exceeds Total Capacity (Supply). Maximization.
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Transportation Method Lecture 20 By Dr. ArshadZaheer
RECAP Transportation model (Minimization) Illustration (Demand < Supply) Optimal Solution Modi Method
Maximization Maximization problem may be solved by the use of following method • Multiply the given pay off matrix of profits or gain by -1. Then use the transportation technique for minimization to obtain optimal solution. • To calculate the total profit or gain multiply the total cost by -1
Illustration • Maximize the profit for this problem
For maximization we multiply all the profits or gains by -1.
Total Profit Total Cost =15*-10 + 15*-9 + 10*-8 + 10*-8 + 15* -20 = -745 Total Profit=-1*- 745 = 745
No of Basic Variables= m+n-1 =4+3-1 =6 m= No of sources n= No of destinations
For calculating shadow cost we need to find the values of U and V variables
Equations U1+V1=-10 let U2=0 U2+V1=-9 U1=-1 V1=-9 U2+V2=-8 U2=O V2=-8 U3+V2=-8 U3=0 V3=-20 U3+V3=-20 U4=20 U4+V3=0
We can calculate all the shadow cost in the same way for others Shadow cost of S1, D3 Vij = (Ui + Vj) –Cij V13 = (U1 + V3) –C13 =(-1-20) -12 =-9
We add θ in maximum positive shadow cost to proceed further because our optimal condition is not yet satisfied
Maximum θ= Min (10,15) ` = 10
Total Cost= 15*-10 +15*-9 + 10*-8 + 25*-20 = -865 Total Profit/Gain = -1 * -865 = 865
Equations U1+V1=-10 let U2=0 U2+V1=-9 U1=-1 V1=-9 U2+V2=-8 U2= 0 V2=-8 U3+V3=-20 U3=-12 V3=-8 U4+V2=0 U4=8 U4+V3=0
shadow costs are still positive so we use θ to proceed further
Maximum θ= Min (10, 15) ` = 10
Total Cost = 5*-10 + 10*-15 + 25*-9 + 25*-20 = - 925 Total Gain/Profit= = -1 * -925 = 925
Equations U1+V1=-10 let U2=0 U1+V2=-15 U1=-1 V1=-9 U2+V1=-9 U2= 0 V2=-14 U3+V3=-20 U3=-6 V3=-14 U4+V2=0 U4=14 U4+V3=0
Criteria for optimality is not satisfied so we will proceed further with use of θ
Maximum θ= Min (5, 10) ` = 5
Total Cost =15*-15 + 25*-9 + 25*-20 = -950 Total Profit/Gain= = -1 * - 950 = 950
Equations U1+V2=-15 let U2=0 U2+V1=-9 U1=-6 V1=-9 U3+V3=-20 U2= 0 V2=-9 U4+V1=0 U3=-11 V3=-9 U4+V2=0 U4=9 U4+V3=0
Criteria for optimality has been satisfied as all the shadow costs are non- positive
Optimal Distribution • S1 ─ ─ ─ ─ > D2 = 15 • S2 ─ ─ ─ ─ > D1 = 25 • S3 ─ ─ ─ ─ > D3 = 25 • Sf ─ ─ ─ ─ > D1 = 5 • Sf ─ ─ ─ ─ > D2 = 5 • Sf ─ ─ ─ ─ > D3 = 5 Total = 80 Total Gain = 950