Archive for January, 2009

Tip: Setting up imports for 2D Graphical Functions

January 29th, 2009 8 comments

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
simple import 1

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:

simple import 2

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…

isee.NET Framework 1.1 – Powering isee NetSim Server

January 28th, 2009 No comments

The isee.NET Framework is a Software Development Kit (SDK), that allows programmers to build applications that use iThink/STELLA models.  For example, programmers like me use it here at isee to build the isee NetSim Server software, which allows iThink and STELLA models to run over the web.  We have quite a few customers using the Framework for other interesting applications.  I’ll be posting more about some of those in the coming months.

A couple of weeks ago we quietly released an update to the isee.NET Framework.  isee.NET Framework version 1.1.   Since the Framework powers isee NetSim Server, over the past year and a half we were adding features, fixing issues and tweaking things for the isee NetSim 1.0 release.

package_developmentIt was a really rewarding experience for me to depend on a product that I helped developed to build a new product.  In the software business we call this “eating your own dogfood” — using your own products within your business.  (And I guess we should be if we’re developing a product for others to make software too).  We depend on the isee.NET Framework as much as our customers do, so it’s a win-win situation.

Head over to the product page to take a look at what is new in the 1.1 release.

Save Time Setting up Data Imports

January 27th, 2009 No comments

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

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.

Categories: Modeling Tips Tags: , , ,