Page 47 - ExtendSim User Guide

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Running a Model 21
Other modifications
Random Number block dialog
Math block dialog
As you have seen, ExtendSim offers many options to
change the way a model runs so that you can explore
different scenarios. The Reservoir model can be
expanded upon in other ways that will be explored later since they involve more advanced techniques. For example, you can:
• Add more real-life contingencies by adding blocks to the model. For example, add more water sources, then use a Notify block (Utilities library) to monitor the simulation and sound an alarm if the water level goes above a certain value. For more information, see “Notify block” on page 589.
• Add blocks and connect them to the Holding Tank to remove some of the water from the Reservoir. The blocks can cause the water to be removed randomly or based on a table of
Random Number block (Stream)
The Random Number block generates values based on a random distribution. In this model, it outputs a real number from 0 to 1.
Change the distribution’s maximum out- put from 1 to a different number, such as 30, and run the simulation again.
☞ ExtendSim lets you choose from dozens of probability distributions or create your own. Learn more in “Proba- bility distributions” on page 704.
Math block
To add a constant value to the input number, enter an amount in the Add field.
The Math block is very versatile. By clicking radio buttons you can quickly change the type of mathematical function that the block performs.
Holding Tank block (Reservoir)
In addition to accumulating the amounts entering, the Holding Tank allows you to enter an initial amount and to remove some or all of the contents. You can also specify which mathematical method is
performed on the inputs to calculate the contents.
Enter an amount in the Initial contents field and run the simulation again to see how the results change.
Other modifications
The Math block can be used to perform any mathematical function. In this model, it is used to add the amounts of water coming in from the rainfall and the stream.
Holding Tank block dialog
Tutorial
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