Problemløser

Åbner dialogen Problemløser. En løser lader dig løse matematiske problemer med flere ubekendte variabler og et sæt betingelser på variabler med målsøgnende metoder.

For at tilgå denne kommando...

Vælg Funktioner - Problemløser


Solver settings

note

The dialog settings are retained until you close the current document.


Target Cell

Enter or click the cell reference of the target cell. This field takes the address of the cell whose value is to be optimized.

Optimize results to

By Changing Cells

Enter the cell range that can be changed. These are the variables of the equations.

Limiting Conditions

Add the set of constraints for the mathematical problem. Each constraint is represented by a cell reference (a variable), an operator, and a value.

note

You can set multiple conditions for a variable. For example, a variable in cell A1 that must be an integer less than 10. In that case, set two limiting conditions for A1.


Options

Opens the Solver Options dialog.

The Solver Options dialog let you select the different solver algorithms for either linear and non-linear problems and set their solving parameters.

Solve

Click to solve the problem with the current settings. The dialog settings are retained until you close the current document.

For at løse ligninger med problemløseren

Målet med problemløserprocessen er at finde de variabelværdier, som resulterer i en optimal værdi i målcellen, som også kaldes "objektet". Du kan vælge om værdien i målcellen skal være den største, mindste eller tættest på en given værdi.

Variablernes begyndelsesværdier bliver indsat i et rektangulært celleområde, som du indtaster i feltet Ved at ændre celler.

Du kan angive en serie begrænsende betingelser, som indstiller begrænsninger for nogle celler. Du kan for eksempel sætte den begrænsning, at en af variablerne eller cellerne ikke må være større end en anden variabel eller ikke større end en given værdi. Du kan også definere den begrænsning, at en eller flere variabler skal være heltal (værdier uden decimaler) eller binære værdier (hvor kun 0 og 1 er tilladte).

Using Non-Linear solvers

Regardless whether you use DEPS or SCO, you start by going to Tools - Solver and set the Cell to be optimized, the direction to go (minimization, maximization) and the cells to be modified to reach the goal. Then you go to the Options and specify the solver to be used and if necessary adjust the according parameters.

There is also a list of constraints you can use to restrict the possible range of solutions or to penalize certain conditions. However, in case of the evolutionary solvers DEPS and SCO, these constraints are also used to specify bounds on the variables of the problem. Due to the random nature of the algorithms, it is highly recommended to do so and give upper (and in case "Assume Non-Negative Variables" is turned off also lower) bounds for all variables. They don't have to be near the actual solution (which is probably unknown) but should give a rough indication of the expected size (0 ≤ var ≤ 1 or maybe -1000000 ≤ var ≤ 1000000).

Bounds are specified by selecting one or more variables (as range) on the left side and entering a numerical value (not a cell or a formula) on the right side. That way you can also choose one or more variables to be Integer or Binary only.