Page 44 - ExtendSim User Guide
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Running a Model
Running the Reservoir model
There is nothing fundamentally different about the structure of these different blocks. Any block may create, modify, or present information, and many blocks perform more than one of these functions. You can, of course, have multiple instances of the same block within a model.
Running the Reservoir model
Now that you have seen the basic parts of a model, you are ready to run the Reservoir simula- tion and see how models operate. After running the model, you will see how easy it is to mod- ify models as you change your assumptions. For now, do not change anything in the blocks’ dialogs.
Select Run > Run Simulation or click the Run Simulation button in the toolbar.
As the simulation runs, progress information will be displayed in the status bar at the bottom left of the model window. (For a simple model like Reservoir that is completed very quickly, the messages may go by too quickly to be read.)
You can learn more about commands for running, stopping, and pausing models in “Running a model” on page 600.
Displaying the results on the Plotter
Plotters show both a graphical representation of the numbers fed to them as well as a table of the numerical values. As described on page 681, ExtendSim comes with a number of flexible plotters to use in your models.
The Reservoir model runs for a simulated 36 months. While the model runs, ExtendSim displays the results on the Plotter, which by default remains on the screen when the simulation is finished. This is your primary method for determining what happened during the simulation.
The Plotter block in this model has information enter- ing three of its four input connectors, so the graph dis- plays three lines. The Plotter also has two value axes, each using a different scale. The legend below the graph indicates which axis is used for each line (Y2 indicates the values are plotted on the right axis) and what each line represents.
Plotter results for the model
In this case, the blue line, labeled 1, is matched with
the left axis to show the total contents of the reservoir over time. Using the right axis, the red line (2) shows the amount of water entering the reservoir from the rainfall alone and the green line (3) shows the input from the stream. (Because the model uses random numbers for the stream, specific values may be different after each run.)
The bottom of a plotter window shows the data points which produce the line. Scroll down this list to see the numerical values for each line. You can also observe the values for any given point by moving the cursor anywhere in the graph. The corresponding values are displayed above the data table’s column headings.
☞ ExtendSim plotters remember the pictures (but not the data) of the last four plots. You can see the previous plots by clicking on the small turned-up page symbol at the bottom left of the graph part of the plot window.
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