Problemlösaren

Opens the Solver dialog. A solver allows you to solve mathematical problems with multiple unknown variables and a set of constraints on the variables by goal-seeking methods.

Solver settings

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

• Maximum: Try to solve the equation for a maximum value of the target cell.

• Minimum: Try to solve the equation for a minimum value of the target cell.

• Value of: Try to solve the equation to approach a given value of the target cell.

  Enter the value or a cell reference in the text field.

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.

• Cell reference: Enter a cell reference of the variable.

  Click the Shrink button to shrink or restore the dialog. You can click or select cells in the sheet. You can enter a cell reference manually in the input box.

• Operator: Select an operator from the list. Use Binary operator to restrict your variable to 0 or 1. Use the Integer operator to restrict your variable to take only integer values (no decimal part).

• Value: Enter a value or a cell reference. This field is ignored when the operator is Binary or Integer.

• Remove button: Click to remove the row from the list. Any rows from below this row move up.

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.

Lösa ekvationer med problemlösaren

Målet med problemlösningsprocessen är att finna de variabla värdena för en ekvation som resulterar i ett optimalt värde i målcellen, som även kallas målfunktion. Du kan välja om värdet i målcellen ska vara ett maximalt, minimalt eller närma sig ett givet värde.

De initiala variabelvärdena infogas i ett rektangulärt cellområde som du anger i rutan Genom att ändra cell.

Du kan definiera en serie villkor som anger begränsningar för en del celler. Du kan t.ex. ange begränsningen att en av variablerna eller cellerna inte får vara större än andra variabler, eller inte större än ett givet värde. Du kan också definiera en begränsning att en eller flera variabler måsta vara heltal (värden utan decimaler) eller binära värden (där endast 0 eller 1 tillåts).

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.