Subject Specific Training: Scripting

1. Subject Specific Training:Scripting September 2008

2. Learning Objective • Upon completing this training, the learner will be able to identify the components of a script; explain the process for writing a script including its application in Supply Chain Guru; and develop a simple script, test the script and review results.

3. Agenda • Scripting Basics • Scripts in Supply Chain Guru • Script Writing • Testing the Script • Check on Learning • Capstone Exercise

4. Materials • Supply Chain Guru installed on computer with proper licenses • Scripting Training Slides • Script Types Quick Reference Sheet • Model Object Dictionary (Excel Version)

5. Scripting Basics • Why do you need to script? • Simulation Engine • Model Objects • Model Variables

6. Why Do We Script? • Create more detailed models • Real world behavior does not fit in any of the “pre-defined” behaviors • Add realistic scenarios • Perform detailed risk analysis

7. SimServer • External Simulation Engine • Reads the Model Configuration File (MCF) • Simulation results loaded into SCG tables • Ability to use animation

8. Scripting Basics: Model Objects • Can be viewed as an independent little machine with a distinct role • The actions or “operators” on the objects are closely associated with the object • The data structures tend to carry their own operators around with them (or at least "inherit" them from a similar object or "class") • Characteristics (its attributes, fields or properties) • Behaviors (the things it can do, or methods, operations or features)

9. Supply Chain Guru Objects

10. Site Object

11. Scripting Basics: Variables • Definition: a value that can change, depending on conditions or on information passed to the program • Variable Scopes • Model Variables • Permanent • Cannot be created in script • Sites, Customers, Products • Dynamic • Change during the simulation • Exist in Collections • Group of objects that should be kept together • Global Variables • Cannot be declared in script • Use the global variables table to declare variables • Local Variables • Pertain only to the executing script • Context Variables • Contains variables and objects that depend upon the context of the script

12. Mode Selection Rule Process Routing Rule Queue Selection Rule Sourcing Policy Make Policy Inventory Policy On Simulation Begins/ Ends On Receive Order Begins/ Ends On Receive Shipment Begins/ Ends Asset Unit Selection Rule Transportation Costs Basis Rule Scripting Basics: Script Types

13. Using Scripts in Supply Chain GuruTM • Scripts Table • Global Variables Table • Debug Level • Practical Exercise

14. Using Scripts: Scripts Table • Name • Script • Script Type • Time First • Occurrences • Interval

15. On Simulation Ends On Receive Order Begins On Receive Order Ends On Receive Shipment Begins On Receive Shipment Ends Asset Unit Selection Rule Transportation Costs Basis Rule Mode Selection Rule Process Routing Rule Queue Selection Rule Sourcing Policy Make Policy Inventory Policy On Simulation Begins Scripts Table: Script Type See The Script Types Quick Reference Card for more information

16. Using Scripts: Global Variables Table • Name • Type • Value • Dimensions • Notes

17. Debug • The Debug statement is the most detailed debugging command available.  During the simulation run, when a Debug statement is encountered, the model will stop execution and begin to run in a line-by-line serial execution mode, displaying the specific model code being executed at each line.

18. Setting the Debug Level • The model must be set at an equal or higher debug level than what is called in script • Accessible in Model Options, Simulation Tab

19. Using Scripts: Practical Exercise • Copy a script which will permanently close a site • Determine the steps to close the site • Tell SimServer what to do • Run the Simulation and view the results

20. Practical Exercise (1) 1. Open the Model: TrainingExercise1_BaseModel_SiteClosedScript 2. In Word or Notepad, write the steps needed to close DC_2 after the second week of the simulation

21. Practical Exercise (2) 3. Tell SimServer how to perform each step Hint: Use “//” to keep SimServer from reading your comments 4. Copy to the Script Table

22. Set the script to run at day 14 Run the Simulation View the Script Log Practical Exercise (3)

23. Practical Exercise (4) • View Simulation Outputs

24. Script Writing • 3 Steps • Scripting Language • Common Problems

25. 3 Steps to for Script Writing • Determine objective • Pseudocode: write down each step in list form • Tell the computer what to do

26. Step 1: Determine Script Objective • What are you trying to do? • Mode Selection vs. Price Adjustments • Risk Analysis • Refer to the Script Type Quick Reference • What is the context variable? • Map back to Model Object • Model Object Dictionary • Scripting Quick Reference Chart

27. Step 2: Write down each step • Use notepad or Microsoft Word • List each and every event from start to end • Use simple language, write as you speak • Recognize if you will need to loop, make a decision, or use a counter during the script execution

28. What to do? When to Stop? When to do it? How Often? Step 3: Tell the computer • Tools • Scripts Table • Model Object Dictionary • Model Object Quick Reference Guide • Script Log

29. Tell the Computer: Sequential Instructions • Define variables to solve the objective (Start) • Devise a method to create a solution (Body) • Determine how to put the solution back into the model (End)

30. Declare A Variable/ Name the Variable Name Space Can contain only alphanumeric and the underscore character Must begin with a letter NOT case sensitive Do not use reserved words All language keywords All model collections True and False Context namespace Contains variables and objects that depend upon the context of the script Examples: nDate, nDemand, nSite Data Types Integer Real Boolean String Date Object Start: Defining Variables “Declare VariableAs Data Type”

31. Start: Setting Variables “Set Variable = ” • Set your variable to an initial value or expression • Must match the data type that you declared it to be • Can use Operators (+, -, /, *) • Model Object • Use Model Object Dictionary

32. Body: Methods • Looping Instructions • For Next • Repeats a block of script a specific number of times Forindex= intialValue Toexpression Block Next • For Each … Next • While Wend • Do Until • Decision Statements • If …Then • If … Then, Else • If … Then, Elseif, Else, End If • Other Statements • Break: Exits the immediately • Continue: Jumps to the next loop iteration bypassing any further block statements • Return: Goes back to the start of the loop

33. Body: Methods (2) • Built In Functions • Math, String, Date, Debug • Specify namesake prefix and enclose arguments in parentheses • Examples: SET Cost = Math.Min(Global.MinCost, Local.ActualCost) The cost will be the smaller cost of the Global and Local variables SET Elapsed = Date.DateDiff(Global.Now(), Model.StartTime, “s”) Determines the elapsed time between the start of the model run and the current time in seconds

34. End the Script • CALL • Example: CALL Debug.Assert(Not ISNull(THESITE)) Ensures that this site is not empty • Assert • Write to Script Log

35. Testing the Script • Script Log • Run Simulation • Open Notepad • Open the Script log • Location- In Model Folder • Debug statements help determine script correctness • Debugging a Script • Syntax Errors • Misspelling or omitting a command • Run time Errors • Script runs into unexpected error (such as declaring a name an integer) • Logic Errors • Typically prevent script and/ or Sim Server from running • Outputs do not make sense

36. Scripting Language • Comments // • Need to add more here

37. Common Scripting Issues • Need to add more here

38. Identify components of a script Explain process for writing a script Apply a script to SCG Develop and test a script Review results Explain reasons for scripting State when you need a script Define model objects and variables Identify key tables for scripting Select the debug level for a model Plan how to write a script Define key script writing terms Apply steps to write a script Practice writing a script Open the Scripts table Write a script Run a simulation which calls a script Perform a DEBUG on a script Identify simulation outputs and locations of logs Check on Learning

39. Capstone Exercise

40. Create a Model • Save model as: Training_Script_A • 1 Product • 3 CZ, 1 MFG • Weekly demand of 10 by each CZ • Each CZ can be sourced from each MFG • LTL Truckload Policy • 1 Asset Types: • Truck_A: Preferred asset, only available on Mondays • Truck_B: More expensive, runs everyday

41. Custom Mode Selection Script • Write a custom Mode Selection Script which will ship via Truck_A on Mondays, and via Truck_B at all other times. • Run the simulation. • Review outputs and analyze model.

42. Questions