Kalkylator för simplexmetoden
Lös optimeringsproblem med simplexmetoden
Räknaren löser det givna optimeringsproblemet med hjälp av simplexalgoritmen. Den lägger till slack-, överskotts- och artificiella variabler vid behov. Om artificiella variabler förekommer används Big M-metoden eller tvåfasmetoden för att bestämma startlösningen. Steg är tillgängliga.
Din inmatning
Maximera $$$Z = 3 x_{1} + 4 x_{2}$$$, under bivillkoren $$$\begin{cases} x_{1} + 2 x_{2} \leq 8 \\ x_{1} + x_{2} \leq 6 \\ x_{2} \geq 0 \\ x_{1} \geq 0 \end{cases}$$$.
Lösning
Problemet i kanonisk form kan skrivas enligt följande:
$$Z = 3 x_{1} + 4 x_{2} \to max$$$$\begin{cases} x_{1} + 2 x_{2} \leq 8 \\ x_{1} + x_{2} \leq 6 \\ x_{1}, x_{2} \geq 0 \end{cases}$$Lägg till variabler (slack- eller överskottsvariabler) för att omvandla alla olikheter till likheter:
$$Z = 3 x_{1} + 4 x_{2} \to max$$$$\begin{cases} x_{1} + 2 x_{2} + S_{1} = 8 \\ x_{1} + x_{2} + S_{2} = 6 \\ x_{1}, x_{2}, S_{1}, S_{2} \geq 0 \end{cases}$$Skriv upp simplextablån:
| Basic | $$$x_{1}$$$ | $$$x_{2}$$$ | $$$S_{1}$$$ | $$$S_{2}$$$ | Lösning |
| $$$Z$$$ | $$$-3$$$ | $$$-4$$$ | $$$0$$$ | $$$0$$$ | $$$0$$$ |
| $$$S_{1}$$$ | $$$1$$$ | $$$2$$$ | $$$1$$$ | $$$0$$$ | $$$8$$$ |
| $$$S_{2}$$$ | $$$1$$$ | $$$1$$$ | $$$0$$$ | $$$1$$$ | $$$6$$$ |
Den inträdande variabeln är $$$x_{2}$$$, eftersom den har den mest negativa koefficienten $$$-4$$$ i Z-raden.
| Basic | $$$x_{1}$$$ | $$$x_{2}$$$ | $$$S_{1}$$$ | $$$S_{2}$$$ | Lösning | Ratio |
| $$$Z$$$ | $$$-3$$$ | $$$-4$$$ | $$$0$$$ | $$$0$$$ | $$$0$$$ | |
| $$$S_{1}$$$ | $$$1$$$ | $$$2$$$ | $$$1$$$ | $$$0$$$ | $$$8$$$ | $$$\frac{8}{2} = 4$$$ |
| $$$S_{2}$$$ | $$$1$$$ | $$$1$$$ | $$$0$$$ | $$$1$$$ | $$$6$$$ | $$$\frac{6}{1} = 6$$$ |
Den avgående variabeln är $$$S_{1}$$$, eftersom den har den minsta kvoten.
Dividera rad $$$1$$$ med $$$2$$$: $$$R_{1} = \frac{R_{1}}{2}$$$.
| Basic | $$$x_{1}$$$ | $$$x_{2}$$$ | $$$S_{1}$$$ | $$$S_{2}$$$ | Lösning |
| $$$Z$$$ | $$$-3$$$ | $$$-4$$$ | $$$0$$$ | $$$0$$$ | $$$0$$$ |
| $$$x_{2}$$$ | $$$\frac{1}{2}$$$ | $$$1$$$ | $$$\frac{1}{2}$$$ | $$$0$$$ | $$$4$$$ |
| $$$S_{2}$$$ | $$$1$$$ | $$$1$$$ | $$$0$$$ | $$$1$$$ | $$$6$$$ |
Lägg till rad $$$2$$$ multiplicerad med $$$4$$$ till rad $$$1$$$: $$$R_{1} = R_{1} + 4 R_{2}$$$.
| Basic | $$$x_{1}$$$ | $$$x_{2}$$$ | $$$S_{1}$$$ | $$$S_{2}$$$ | Lösning |
| $$$Z$$$ | $$$-1$$$ | $$$0$$$ | $$$2$$$ | $$$0$$$ | $$$16$$$ |
| $$$x_{2}$$$ | $$$\frac{1}{2}$$$ | $$$1$$$ | $$$\frac{1}{2}$$$ | $$$0$$$ | $$$4$$$ |
| $$$S_{2}$$$ | $$$1$$$ | $$$1$$$ | $$$0$$$ | $$$1$$$ | $$$6$$$ |
Subtrahera rad $$$2$$$ från rad $$$3$$$: $$$R_{3} = R_{3} - R_{2}$$$.
| Basic | $$$x_{1}$$$ | $$$x_{2}$$$ | $$$S_{1}$$$ | $$$S_{2}$$$ | Lösning |
| $$$Z$$$ | $$$-1$$$ | $$$0$$$ | $$$2$$$ | $$$0$$$ | $$$16$$$ |
| $$$x_{2}$$$ | $$$\frac{1}{2}$$$ | $$$1$$$ | $$$\frac{1}{2}$$$ | $$$0$$$ | $$$4$$$ |
| $$$S_{2}$$$ | $$$\frac{1}{2}$$$ | $$$0$$$ | $$$- \frac{1}{2}$$$ | $$$1$$$ | $$$2$$$ |
Den inträdande variabeln är $$$x_{1}$$$, eftersom den har den mest negativa koefficienten $$$-1$$$ i Z-raden.
| Basic | $$$x_{1}$$$ | $$$x_{2}$$$ | $$$S_{1}$$$ | $$$S_{2}$$$ | Lösning | Ratio |
| $$$Z$$$ | $$$-1$$$ | $$$0$$$ | $$$2$$$ | $$$0$$$ | $$$16$$$ | |
| $$$x_{2}$$$ | $$$\frac{1}{2}$$$ | $$$1$$$ | $$$\frac{1}{2}$$$ | $$$0$$$ | $$$4$$$ | $$$\frac{4}{\frac{1}{2}} = 8$$$ |
| $$$S_{2}$$$ | $$$\frac{1}{2}$$$ | $$$0$$$ | $$$- \frac{1}{2}$$$ | $$$1$$$ | $$$2$$$ | $$$\frac{2}{\frac{1}{2}} = 4$$$ |
Den avgående variabeln är $$$S_{2}$$$, eftersom den har den minsta kvoten.
Multiplicera rad $$$2$$$ med $$$2$$$: $$$R_{2} = 2 R_{2}$$$.
| Basic | $$$x_{1}$$$ | $$$x_{2}$$$ | $$$S_{1}$$$ | $$$S_{2}$$$ | Lösning |
| $$$Z$$$ | $$$-1$$$ | $$$0$$$ | $$$2$$$ | $$$0$$$ | $$$16$$$ |
| $$$x_{2}$$$ | $$$\frac{1}{2}$$$ | $$$1$$$ | $$$\frac{1}{2}$$$ | $$$0$$$ | $$$4$$$ |
| $$$x_{1}$$$ | $$$1$$$ | $$$0$$$ | $$$-1$$$ | $$$2$$$ | $$$4$$$ |
Addera rad $$$3$$$ till rad $$$1$$$: $$$R_{1} = R_{1} + R_{3}$$$.
| Basic | $$$x_{1}$$$ | $$$x_{2}$$$ | $$$S_{1}$$$ | $$$S_{2}$$$ | Lösning |
| $$$Z$$$ | $$$0$$$ | $$$0$$$ | $$$1$$$ | $$$2$$$ | $$$20$$$ |
| $$$x_{2}$$$ | $$$\frac{1}{2}$$$ | $$$1$$$ | $$$\frac{1}{2}$$$ | $$$0$$$ | $$$4$$$ |
| $$$x_{1}$$$ | $$$1$$$ | $$$0$$$ | $$$-1$$$ | $$$2$$$ | $$$4$$$ |
Subtrahera rad $$$3$$$ multiplicerad med $$$\frac{1}{2}$$$ från rad $$$2$$$: $$$R_{2} = R_{2} - \frac{R_{3}}{2}$$$.
| Basic | $$$x_{1}$$$ | $$$x_{2}$$$ | $$$S_{1}$$$ | $$$S_{2}$$$ | Lösning |
| $$$Z$$$ | $$$0$$$ | $$$0$$$ | $$$1$$$ | $$$2$$$ | $$$20$$$ |
| $$$x_{2}$$$ | $$$0$$$ | $$$1$$$ | $$$1$$$ | $$$-1$$$ | $$$2$$$ |
| $$$x_{1}$$$ | $$$1$$$ | $$$0$$$ | $$$-1$$$ | $$$2$$$ | $$$4$$$ |
Inga av Z-radens koefficienter är negativa.
Optimum har uppnåtts.
Följande lösning erhålls: $$$\left(x_{1}, x_{2}, S_{1}, S_{2}\right) = \left(4, 2, 0, 0\right)$$$.
Svar
$$$Z = 20$$$A uppnås vid $$$\left(x_{1}, x_{2}\right) = \left(4, 2\right)$$$A.