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with a local optimum or an imprecise results, repeated searches are made from different
initial policy parameter values chosen randomly. You can change the seed for random
variations in initial policy parameters. As will be seen later, initial policy parameters
can also be changed manually.
Figure 5.4 shows page 2 for Assumptions. On the left hand side are symbols for
all constants and initial stock values in the Studio model. Click on one of the
candidates. It shows up under Assumptions and the original symbol becomes grey. If
you want to deactivate it again, remove the tick. NOTE: Do NOT click on policy
parameters under Assumptions. If you enter a policy parameter, and even if you
deactivate it again, the value you set in page 2 will override the initial policy parameter
values that shall be set in pages 3 and 4.
Under Sampling you can choose between settings for Initial values or time Series.
For initial stock values and parameters that do not change over time, choose Initial. For
random variables that change over time, choose Series. The Series-example in Figure
5.4 is randomness, which had to be a constant in the Studio model. Under Type, you
can choose type of variation; the mini-window shows the alternatives. Either the
parameter has a fixed value or it varies randomly with a choice between the following
distributions: exponential, normal, triangular, truncated normal, and uniform. Here we
choose normal for randomness.
Figure 5.4: Page 2 - Assumptions