Documentation/AOO4 User Guides/Calc Guide/Data Analysis/Using the Solver

Apache OpenOffice 4.1 Calc Guide

Chapter 9: Data Analysis

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• Introduction
• Consolidating Data
• Creating Subtotals
• Using “What If” Scenarios
  • Creating Scenarios
  • Settings
  • Changing Scenarios
    • Changing Scenario Properties
    • Changing Scenario Cell Values
  • Working with Scenarios Using the Navigator
  • Tracking Values in Scenarios
• Using Other “What If” Tools
  • Multiple Operations in Columns or Rows
    • Calculating with One Formula and One Variable
    • Calculating with Several Formulas Simultaneously
  • Multiple Operations Across Rows and Columns
    • Calculating with Two Variables
• Working Backwards Using Goal Seek
  • Goal Seek Example
• Using the Solver
  • Solver Example

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Tools → Solver amounts to a more elaborate form of Goal Seek. The difference is that Solver deals with equations with multiple unknown variables. It's specifically designed to minimize, maximize, or reach a target with a result following a set of rules you define.

Each of these rules defines whether an argument in the formula should be greater than, less than, or equal to the figure you enter. If you want the argument to remain unchanged, you must enter a rule that specifically states that the cell should be equal to its current entry. For arguments that you would like to change, you need to have at least one rule for each. If you are trying to maximize or minimize the result, you probably need two rules to define a range of possible values. Otherwise, Solver will use unrealistically large or small values. You can also set constraints that one of the variables or cells must not be bigger than another variable or that one or more variables must be integers (values without decimals) or binary values (where only 0 and 1 are allowed). Without a specific example to think about, setting the constraints in Solver may sound very difficult. In a real situation, the constraints are likely to be obvious. Practical considerations will often be your guide.

Once you have finished setting up the rules, click the  Solve  button to begin the automatic process of adjusting values and calculating results. Depending on the complexity of the task, this may take some time.