Making Connections

Sarah Davie Modeling Tips

iThink and STELLA version 9.0 introduced a powerful new feature: data import and export with Excel.  Here at isee, we were excited to hear from our customers about how much they appreciated the feature and how easy it was to use.  In fact, many customers told us that it was the major reason they upgraded to version 9.0

Setting up a data import from Excel is pretty straight forward:  type the name of the model variable in one cell, type the value you want to import in the cell below it, (or beside it if you are using horizontal orientation):

If you are importing a time series or graphical function, you just keep listing the data points in the cells below the variable name:

This kind of data formatting works well since an Excel sheet is made up of columns and rows.  But how do you format data that is harder to visualize?  Things get a little tricky when you start dealing with arrayed variables.  The most complex import is a 2 dimensional array of graphical functions.  It’s actually 3 dimensions!

I’ve put together a simple example to illustrate how to do this.

Read more…

2D array, arrays, graphical function, import

Joanne Egner Modeling Tips

Setting up an Excel spreadsheet to import data into your model is easy when you’ve got just a few variables but it can get cumbersome when you’ve got lots of variables, especially if some of them are arrayed.

If you want to avoid lots of copying, pasting, and switching back and forth between your model and Excel, we suggest using the export data feature to set up your data import spreadsheet.

Below are a few simple steps that can save you a bunch of time and headache:

Click to expand

1. In your model, create a Table with all of the variables that you want to import data to.
2. From the Edit menu, choose Export Data. The Export Data dialog will appear.
3. Under “Export Type”, select One Time.
4. Under “Export Data Source”, select Export variables in table and select the table that you created in Step 1.
5. Under “Interval”, select One set of values.
6. Under “Export Destination”, Browse to an empty Excel file and Worksheet Name that you have created for your data import.
7. Select the “Data Orientation” that you prefer.
8. Click OK.

Voila! Your import sheet should be all set to enter data values for each of the variable names AND it will be in the correct format.

data, Excel, export, import