What Is Optimization Toolbox?

linprogDiagnosticsLarge-Scale OptimizationThefirststageofthealgorithmmightinvolvesomepreprocessingofthe constraints (see “Large-Scale Linear Programming” on page 4-15).Several possible conditions might occur that cause linprog to exit withan infeasibility message. In each case, the exitflag argument returnedby linprog issettoanegativevaluetoindicatefailure.If a row of all zeros is detected in Aeq but the corresponding element ofbeq is not zero, the exit message isExiting due to infeasibility: An all-zero row in theconstraint matrix does not have a zero in correspondingright-hand-side entry.If one of the elements of x is found not to be bounded below, the exitmessage isExiting due to infeasibility: Objective f'*x isunbounded below.If one of the rows of Aeq has only one nonzero element, the associatedvalue in x is called a singleton variable. In this case, the value ofthat component of x can be computed from Aeq and beq. Ifthevaluecomputed violates another constraint, the exit message isExiting due to infeasibility: Singleton variables inequality constraints are not feasible.If the singleton variable can be solved for but the solution violates theupper or lower bounds, the exit message isExiting due to infeasibility: Singleton variables inthe equality constraints are not within bounds.8-137