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Linear Programming. ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry. Recognition and Definition of the Problem. Formulation and Construction of the Mathematical Model. Real-World Problem. Interpretation
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Linear Programming ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
Recognition and Definition of the Problem Formulation and Construction of the Mathematical Model Real-WorldProblem Interpretation Validation and Sensitivity Analysis of the Model Solution of the Model Implementation Linear Programming Modeling Process ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
Linear Programming Mathematical Model • decision variables • linear objective function • maximization • minimization • linear constraints • equations = • inequalities or • nonnegativity constraints ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
2 types of wooden toys: truck train wood - unlimited carpentry labor – limited finishing labor - limited • Inputs: • Demand: trucks - limited trains - unlimited • Objective: maximize total profit (revenue – cost) Linear Programming Example - Pinocchio ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
Linear Programming Example - Pinocchio ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
x2 Objective function z Optimal solution x1 Linear Programming Graphical Solution of LP Problems Feasible area ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
Feasible area - convex set A set of points S is a convex set if the line segment joining any pair of points in S is wholly contained in S. Convex polyhedrons Linear Programming Graphical Solution of LP Problems ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
Feasible area – corner point A point P in convex polyhedron S is a corner point if it does not lie on any line joining any pair of other (than P) points in S. Linear Programming Graphical Solution of LP Problems ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
Basic Linear Programming Theorem The optimal feasible solution, if it exists, will occur at one or more of the corner points. Simplex method Linear Programming Graphical Solution of LP Problems ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
x2 3000 E D 2000 C 1000 B A x1 1000 2000 0 Linear Programming Graphical Solution of LP Problems ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
Slack/Surplusvariable Slack/Surplusvariable = 0 > 0 Linear Programming Interpretation of Optimal Solution • Decision variables • Objective value • Binding / Nonbinding constraint (or ) ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
x2 A z x1 Linear Programming Special Cases of LP Models Unique Optimal Solution ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
x2 B z C x1 Linear Programming Special Cases of LP Models Multiple Optimal Solutions ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
x2 z x1 Linear Programming Special Cases of LP Models No Optimal Solution ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry
x2 x1 Linear Programming Special Cases of LP Models No Feasible Solution ___________________________________________________________________________ Quantitative Methods of Management Jan Fábry