:REPORT TXT1 :TITLE TXT1 :FONT Times New Roman|12||0-0-0 You may need to use the scroll bars to the right and on the bottom to see all of the information contained in this window. Welcome to Vensim. This software is designed to let you evaluate Vensim to see if it is suitable to your needs and experience. The demo allows you to learn a little bit about how Vensim works, and then to work with Vensim itself. The Vensim Demo is intended for evaluation purposes only. You must use Vensim in accordance with the license agreement and subject to the restrictions in paragraph 4. The demonstration copy of Vensim is constructed as a Vensim Application (Venapp). Vensim Applications are models packaged with a customized user interface that allow exploration and analysis of a specific model. Vensim Applications organize the functionality of Vensim so that a model can be analyzed without learning how to use Vensim itself. This demo allows you to learn something of how Vensim can be used, and to explore a number of different models to better understand how Vensim operates. Finally, you can experiment with the development version of Vensim which is more powerful but less controlled and directed. The normal development functionality of Vensim can be accessed by selecting the appropriate menu item from the Main Menu, or by closing this window from the box in the upper left hand corner. You can close this window anytime and continue working with the model you are using inside Venapp. If you choose to work with Vensim in its development form and wish to return to this menu driven format, select the Model>Demo command from the Vensim Workbench menu. There are four models available for use and analysis using the Vensim Application environment. You can choose among these different models from the Main Menu. Each of the models is stored in a separate subdirectory. There are a number of additional models available in the directory in which this demonstration was installed. If you open the Text Edit tool on these models you will see a brief commentary on the nature and source of the model. The demonstration copy of Vensim contains the full functionality of Vensim with the following exceptions: 1. The software will close after 2 hours of inactivity. 2. Nothing can be copied or exported to the clipboard. 3. Nothing can be pasted from the clipboard. 4. Models cannot be read in equation only format. 5. Printed output is marked "demonstration version". 6. Changes made to models or files cannot be saved. 7. Only models shipped with the Demo can be used. If you have problems, questions, or would like to order Vensim please call us at 508 651 0432. Good luck, and have fun. :END-OF-REPORT :REPORT TXT2 :TITLE TXT2 :FONT Times New Roman|12||0-0-0 VensimTM the VentanaTM Simulation Environment VenappTM the VensimTM Application Environment 1. System Requirements To use this Demo you will need a PC compatible computer running Microsoft WindowsTM version 3.0 or 3.1. The Demo requires two megabytes of disk space and at least two megabytes of memory to function well. Unless you made a special request, the software is shipped on one high density 3.5 inch diskette. 2. Installing the Demo To install the Demo insert the Demo disk into drive A or drive B. Then, at the DOS prompt, type A:INSTALL or B:INSTALL. If you are running windows then use the File>Run command of the program manager, type A:INSTALL or B:INSTALL in the command line and click OK. The installation program will ask you where you want to install the Demo. Normally the demo will be installed in the directory C:\\VENDEMO. You may choose a different disk or directory. The Demo is designed so that any files created during installation and use of the Demo will be contained in the directory it is installed in, or a sub-directory thereof. NOTE Installing the Demo will not make any modifications to your existing files. 3. Starting the Demo If you are running Windows you start the Demo by invoking the File>Run command from the Program Manager, and then entering the full path and name for the Demo (normally C:\\VENDEMO\\VENDEMO). To start the Demo from DOS change to the directory the Demo is installed in and type WIN VENDEMO at the DOS prompt. 4. Using the Demo When the Demo starts you will find yourself inside of a menu driven Vensim Application (Venapp). You can use the up and down arrow keys and the Enter key to choose between menu items, or the mouse to click on menu items. A straightforward explanation of what Vensim does can be obtained by pressing the Enter key repeatedly. You can explore a number of different Vensim Applications using the demo. You may also, if you wish, look at the Vensim Development Environment, a powerful and flexible user directed environment for developing and working with models. Section 8 below gives a brief description of basic operations in the Vensim Development environment. After exiting the Demo, you may, if you wish, start the Demo again from step 3. NOTE The Demo will terminate automatically after two hours of inactivity. This is a security measure. If you return to your computer and the Demo is no longer active you may restart it by going back to step 3. 5. Removing the Demo The Demo will not modify any of your existing files, or create any files outside of the directory it is installed in. To remove the Demo you simply need to erase the files in the directory you installed the Demo and each sub-directory thereof. A utility named VENDELET.exe is included to make this more convenient. To remove the Demo, at the DOS prompt use the CD command to change directory to the directory the Demo is installed in, and then type VENDELET. For example if you installed the Demo in C:\\VENDEMO you would type: C: CD \\VENDEMO VENDELET You will be asked if you want to delete all the files in five directories. Normally you will just answer yes each time. The purpose of this prompt is to prevent you from inadvertently deleting a file you may wish to keep. If you installed the Demo in a directory you did not previously have, and did not place any other files in that directory or its sub-directories you will want to answer yes to deleting all the files. After you remove the Demo you may, if you wish, try the Demo again by starting at step 2. 6. License The Vensim Demonstration Disk is provided to you for evaluation purposes only and is subject to the terms of the license agreement the disk is enclosed in. The Demo software may not be used in any consulting or commercial activity. 7. Questions and Comments We will be happy to answer your questions and would like to hear your comments. Please contact us: Vensim Product Center, Ventana Systems, Inc., 60 Jacob Gates Road, Harvard MA 01451, USA. vensim@vensim.com Phone: 508 651 0432. 8. Vensim Development Environment When you start the Demo you will be inside a Vensim Application. Vensim Applications contain a model, and directed way of interacting with a model. They are intended to help people unfamiliar with modeling interact and learn from existing debugged and refined models. The Vensim Development Environment lets you create, refine and debug models quickly and effectively. 8.1 Workbench-Toolbox Vensim uses a Workbench-Toolbox metaphor to help you work with models. The Workbench is the main Vensim window, and it is labeled "Vensim Workbench." It always contains a model, and the model is always positioned at a variable - called the Workbench variable. When you click on a tool, the tool is applied to the Workbench variable of the Workbench model. For example, clicking on the Causes Tree tool will create a tree showing the causes of the Workbench variable. A Toolbox - accessible using the Toolset>Add Tool command - allows you to add new tools to the Workbench. Shift clicking on a tool on the Workbench allows you to modify the behavior of that tool. 8.2 Changing the Workbench Variable You can change the Workbench Variable by double clicking on a different variable name appearing in any Vensim window - trees, graphs, tables and so on. There is also a variable selection window accessible from the Var>Select menu item on the Workbench. You can do wildcard pattern matching, or select variables by type from this window. 8.3 Datasets Simulation results are called datasets. You can load up to 8 datasets into Vensim to compare the behavior of variables. The datasets do not have to come from the same model. The Datasets>Load command allows you to load and unload datasets. When you do a simulation, the corresponding dataset is automatically loaded. 8.4 Simulations To start a simulation use the Datasets>Simulate command. A dialog box will appear asking you for input. For simple simulations you will probably just want to name the simulation, modify constants or lookups, and run the simulation. If you ask to run a simulation with the name of an existing dataset, you will be asked if you want to overwrite the old dataset. 8.5 Controlling Output There are a number of dialogs that allows you to control the amount and appearance of output. Most important are the dialog brought up by the Globals>Time Axis, and Globals>Scaling command. Note that shift clicking on graphs can also be used to change the displayed time ranges. 8.6 Sketch Tool The Sketch tool is used to graphically display and modify information about cause and effect. To activate it click on the tool labeled Sketch, or use the Model>Sketch menu item. Once the Sketch tool is activated you can use it to create and modify cause and effect diagrams. A number of sub-tools appear to the left of the window the sketch appears in, and operate similarly to tools found in draw programs. 8.7 Modifying Equations Vensim is designed so that models can be entered both visually and algebraically. You can do one without the other, but to simulate a model you will need to create equations. You can modify the model equations one at a time using the Equation Edit tool. If you Ctrl-Click on a name on the sketch, or click on the Equation Edit tool the Equation Editor will start. Vensim will make sure the sketch is kept correct if you make changes using the Equation Editor. You can also modify model equations using the Text Edit tool. Click on the Text Edit tool or select the Model>Edit command. The straightforward Text Editor will appear allowing you to change equations. You can create equations in any order. Vensim will order them automatically and tell if you if there are problems before it simulate the model. NOTE To create a Level or State variable in Vensim use the INTEG function as in: Water Level = INTEG(inflow-outflow,INITIAL WATER LEVEL). 8.9 Existing Models The Vensim Demo is shipped with a number of models. Four of these models are put in separate sub-directories, and a number are included in the main VENDEMO directory. You can load the different models using the Model>Load command. 8.10 Printing If you want to work by example, and this is highly recommended, than you may find it useful to print off one or more of the models included with the demo. To do this start the Text Edit tool using the Model>Edit command, then select the File>Print menu item from the Text Editor. For security reasons there will be a mark printed in the middle of the paper, but the output should be quite legible. 8.11 Developing a model The following two pages take you through the development and use of the simples possible model using Vensim. This process is intended to give you a chance to work hands on with the Vensim development environment. 8.12 Other Features There is not sufficient space to go into all of the features of Vensim here, and the on-line help capabilities are not, as yet, in place. You are, of course, welcome to experiment. If you have specific questions about capabilities please contact us. ************* Simple Population Model ******************** Step by Step This two page guide shows you how to develop and use a simple model of population in Vensim. The steps are numbered, and no prerequisite knowledge is assumed. The problem is to develop the simplest possible model of population growth. 1. Exit the demo to the Vensim development environment by selecting this option from the main menu. 2. From the Vensim Workbench menu select the command Model>New. 3. Click on the sketch tool icon (labeled Sketch), or select the menu item Model>Sketch. 4. In the new window that appears (labeled "On-line Model without name View: 1"), click on the word icon () and position the pointer over the empty area of the window. 5. Click on the window, an editing box should appear, type the word "Population" into the editing box. Click somewhere else and type the word "births". Continue clicking and typing the words "birth rate", "deaths", "death rate". The window should look like this: 6. Click on the curved arrow tool () and then click on the work "Population" in the sketch. As you move the cursor an arrow should follow. Click on the work "births", an arrow should connect the two. Drag the circle in the middle of the arrow to reshape the arrow. (To drag, press the mouse button over the circle and then move the mouse without releasing the mouse button.). Continue making connections from: deaths --> population death rate --> deaths Population ---> births births ---> Population birth rate --> births This should leave you with: If you do not reshape the double arrows between "Population" and "deaths" (or "Population" and "births") the arrows will sit on top of one another and not be completely visible. 7. You have now completely specified the structure for the model. Next you need to specify the equations precisely defining that structure. Hold down the Control (Ctrl) key and click on "Population." The Equation Edit tool will appear as: 8. Complete the equation for population as Population=INTEG(births - deaths,100) You can type this in (beginning with the = sign) or click on the various symbols appearing in the buttons and lists. The INTEG function, for example, is in the function list, just below INITIAL. The INTEG function defines population as an accumulation or Level variable. The 100 is the initial value of the variable. 9. After you have completed the equation click on the Finish button. You will see a list of errors reported: 10.The errors all relate to incomplete definitions. Click on any of these errors to go to the corresponding equations. Continue inputting equations in this manner, clicking on the Finish button to get a list of what is not yet completed after each equation is entered. The remaining equations requiring entry are: births = Population * net birth rate net birth rate = .06 deaths = Population * death rate death rate = .04 After you enter the last equation, and click on the Finish button the Equation Editor will disappear, your model is complete. NOTE if you make syntax errors during equation entry the finish button will describe your error, and position the cursor where the error was detected. Spacing and capitalization are not important. Use whatever you want to maximize readability and clarity. 11.To simulation the model select Datasets>Simulate from the Vensim Workbench Menu. You will see a simulation control dialog. Type in a new name ("pop1" as an example) for the simulation and click OK. The simulation will begin. 12.To view the simulation results select Variable>Select from the Vensim Workbench menu. From the list of variables that appears double-click on population. The name population should appear in the workbench. Now click on the tool () labeled "Causes Strip." You should see a graph of population and its causes: 13.You have created a model, made a simulation and used the tools of Vensim to view the simulation results. You can continue to explore the model and its results with Vensim tools. As an experiment, click on each of the tools in turn and look at the output it generates. :END-OF-REPORT :GRAPH WIP1 :TITLE Workforce and Productivity after a Sales Step :WIP :X-MIN 0 :X-MAX 100 :SCALE :VAR sales|Sales :Y-MIN 50 :Y-MAX 150 :SCALE :VAR Workforce|Workforce :Y-MIN 50 :Y-MAX 150 :SCALE :VAR productivity|Productivity :Y-MIN 0.5 :Y-MAX 1.5 :REPORT SILLY :TITLE SILLY :FONT Times New Roman|12||0-0-0 This is a silly report. Starting Workforce= \Workforce?100=Normal Value?119.68=Final Value@0/ Midle Workforce= \Workforce?100=Normal Value?119.68=Final Value@50/ Final Workforce= \Workforce?100=Normal Value?119.68=Final Value@100/ Net hires @36 = \Net Hires?-3=Special@36/ Net hires @38 = \Net Hires?-3=Special%5.5g@38/ :END-OF-REPORT