tailieunhanh - Financial Modeling with Crystal Ball and Excel Chapter 6

CHAPTER 6 Selecting Run Preferences Now that we have covered the basics of setting up a Crystal Ball model and using its forecasts to help you make decisions, we will take a closer look at the options available to you through the Run Preferences menu to control the execution of your simulation models. | 6 Selecting Run Preferences Now that we have covered the basics of setting up a Crystal Ball model and using its forecasts to help you make decisions we will take a closer look at the options available to you through the Run Preferences menu to control the execution of your simulation models. TRIALS Figure shows the Trials tab of the Run Preferences dialog. A Crystal Ball trial is the process of generating random variates from the stochastic assumptions you have defined for your model evaluating the formulas that depend on these values then calculating and storing the forecast values. When you click the Run button Crystal Ball begins executing the steps depicted in Figure . The actions taken by Crystal Ball at each step are described as follows Start is where Crystal Ball prepares itself to run a simulation by looking for the assumption and forecast cells in your spreadsheet and getting ready to store forecast values in your computer s memory. Set Values is where each trial begins by Crystal Ball generating a random value for each stochastic assumption and placing it in the corresponding assumption cell. Recalculate is where Crystal Ball instructs Excel to use the values that were just placed in the assumption cells to update each cell in the spreadsheet that depends on the assumptions. Get Results is where Crystal Ball takes the updated value from each of the forecast cells and stores it in memory. If you have enabled sensitivity analysis Crystal Ball also stores the current value of each assumption cell during this step for possible analysis later with sensitivity charts. Stop marks the completion of each simulation trial. If none of the stopping criteria described below have been satisfied Crystal Ball returns to the Set Values step as indicated in Figure . End is where Crystal Ball returns control to Excel after one of the stopping criteria is met or after you have clicked on the Stop button in the Crystal Ball toolbar. 95 96 FINANCIAL MODELING WITH .