BU275 Lecture Notes - Lecture 6: Shadow Price, Feasible Region, Reduced Cost
Document Summary
Assignment due feb 1: 12-2 tues/thurs, lh 4073. Types of solutions: one optimal solution, (infinitely) many optimal solutions, unbounded ("optimal" z=infinity, infeasible. Your constraints may eliminate all feasible points, so there is no feasible region: the problem is infeasible, regardless of the objective function, solver: could not find a feasible solution. For given constraints changing the objective function could cause: one optimal solution, many optimal solution (solver only shows 1) Two different x-values, same z: unbounded (solver: does not converge) Or objective function is wrong (max or min problem) Based on mixing feed+ problem: new variable: wheat, new constraint: fat requirement ((cid:3409), objective function. Min 0. 5x1+0. 7x2+0. 8x3: objective coefficient, objective value. Basic variables: a variable (xi) that is not 0 in the optimal solution (final value in sensitivity analysis, (also: reduced cost=0) Non-basic variables: a variable that is 0 in the optimal solution (reduced cost is not 0) Variabl es (change s to objectiv e function coefficie nts)
