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When we run the solver, three responses are possible. In the best case (see Figure 1), the solver finds the solution and offers three reports. Two other cases are possible: the solver finds no feasible solution - then you put constraints incompatible - or he finds a solution infinite - you do not put enough stress

... Let's look at where the solution been found. Then simply select one or more reports in the window and validate to obtain them.

Each report takes a leaf placed upstream of the active sheet. Regret over the names of such sheets: they are too long, with
"Answer Report 1", "Sensitivity Report 1", "Limits Report 1". For my part, I have them named "Responses", "sensitivity" and
"Limitations": it is rarely effective to have names of tabs feature.

Whatever your goal, maximization, minimization or target value, the only report that gives you real information useful is the sensitivity report. It had been translated into the first version of Excel Solver. Alas, in later - and for over 15 years! - It is horribly mistranslated: either Microsoft has used a machine translation software, or the work was entrusted to a trainee with IQ below 100 ...

To tell you how it's bad, imagine, then, that the term "Shadow cost "has been translated as" shadow cost ", a term that I will not find in any book of French economy! Translation is not only filthy, but the presentation of results is not consistent with that of conventional optimization software, so I've developed for my clients a macro that converts the infamous relative sensitivity of the solver of Excel in a report useful and effective.

really useful information found in the report of sensitivity is precisely the marginal value (or the shadow cost Reduced cost, depending on the block in question), and the interval in which it is valid.

Take the case of the B10 cell (plant 2 to warehouse A). This cell is blank, there is nothing in transporting the optimal solution. If we had to carry a unit to continue to respect the constraints online column, he should make a move according to the four corners of the red rectangle (see Figure 3): B10 add, remove as E10, E11 add and remove in B11. This would represent an additional cost of EUR 8: +3, -1, +14, -8. Well, it is precisely the result shown in E14 in the sensitivity report!

This kind of useful information found in the report of sensitivity!