The Molecules are now included in the Vensim installation, though they are subject to a separate license. The master molecule file is accessed from the Windows>Molecules menu item. If you want to browse or edit the molecules files, they are located in the help system, in the Models\Molecules directory.

 

Documentation on individual Molecules is contained in the file molecule.pdf (an Adobe Acrobat format file) that is installed with the molecules.  A short tutorial on molecules is later in this manual.

 

Molecules and their implementation represent work in progress. Comments and suggestions are welcome. They should be sent by email to Jim Hines.

 

The molecules are available from our website  menu item.  The first time you do this you may be asked for to location.

Just navigate to the place you installed them (normally c:\program files\Vensim\molecule\})and select molecule.mdl.  After that when you ask for the molecules you should see the molecule window:

Click on one of the molecule names to open it.  For example the Traditional Coflow

The molecules are complete little models, but you can’t simulate them from the molecule window.  You can, however, peek at the equations by holding down the Ctrl+Shift keys and clicking on the variables.  You can copy and paste them too other places.

From our experience with molecules there are most useful for study.  Why you can copy and paste them the terminology and units all need to be changed anyway and this doesn’t really save much time.  In addition, it is often appropriate to make small changes to the molecules to adapt them to new situations.