Manual Part 00 - Tutorial 02.pdf

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TRUE

TEMPORAL REASONING UNIVERSAL ELABORATION

MANUAL beta Version 20100629

PARTIE 00

Tutorial 02

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ContentsI - INTRODUCTION...................................................................................................................................3

A) Overview of the tutorial.......................................................................................................................3B) Studied model......................................................................................................................................4

1. Vensim Houses model structure........................................................................................................42. Vensim Houses model equation.............................................................................................. ..........53. TRUE Houses model structure..........................................................................................................6

II MODEL.................................................................................................................................................7A) Create a new empty model...................................................................................................................7B) Save model as................................................................................................................................... ...7C) Setting the date.....................................................................................................................................8D) Setting the grid.....................................................................................................................................9

III FRAME..............................................................................................................................................10A) Create new frame...............................................................................................................................10B) Setting the new frame......................................................................................................... ...............11C) Customize frames...............................................................................................................................12

IV STOCKS..................................................................................................................................... .......14A) Create stocks......................................................................................................................................14

1. Create stocks used as constant variables..........................................................................................142. Setting the new stocks.....................................................................................................................153. Rename and initialise the stocks......................................................................................................154. Create stocks updated by flows.................................................................................................... ...165. Rename and initialise the stocks......................................................................................................16

V FLOWS...................................................................................................................................... .........19A) Create links........................................................................................................................................19

1. Rename the link L :......................................................................................................................192. Editing the link TPlanning :.............................................................................................................203. Setting the temporal parameters of the action of the link TPlanning...............................................21

4. Set the default temporal parameters.................................................................................................225. Create the 3 following links as below..............................................................................................23B) Create virtual links.............................................................................................................................24

1. Rename virtual links........................................................................................................................24C) Setting the chronologies.....................................................................................................................26

1. Chronologies of the actions of the links which update the stocks....................................................262. Chronologies of the actions of the virtual links...............................................................................27

D) Editing the procedures of the actions of the links..............................................................................281. Equation of the action of the link TPlanning...................................................................................282. Equations of the actions of the other links.......................................................................................29

E) Editing the procedures of the actions of the virtual links....................................................................301. Equation of the actions of the virtual links......................................................................................30

VI COMPUTE THE MODEL.................................................................................................................31A) Compute the model for one cycle................................................................................................ ......31B) Compute the model for several cycles................................................................................................32

VIII DISPLAY THE MODEL.................................................................................................................33A) Display the values of the model after computing...............................................................................33

IX DISPLAY VALUES IN TABLE........................................................................................................33

TEMPORAL REASONING UNIVERSAL ELABORATIONPage 2

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I - INTRODUCTION

A) Overview of the tutorial

The tutorial has been designed to progressively teach you how to use TRUE. By following this course:

you will discover the main concepts explained here informally; these are the concepts you need tolean and understand.

As you progress through the tutorial, if you want to take a closer look at a concept or if you wand to getmore details, see the other User-Manuals, but it is recommended to read them first.


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B) Studied model

The studied model is Houses :

This model is based on Houses.mdl from VensimPLE.See Vensim.hlp, User's Guide, chapter 11 Games in Vensim.

More on http://www.vensim.com/documentation/toclist.htm

1. Vensim Houses model structure

Houses model is a model of construction in the real estate industry.A long delay exists between the need to close the gap in houses and the completing of construction of those houses.This model features a negative feedback loop with several delays.


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2. Vensim Houses model equation

Time Bounds are :

INITIAL TIME = 0FINAL TIME = 100TIME STEP = 0.5Units for Time : Month

time to respond to gap = 8time to plan to build = 3time to build houses = 6average house life = 1200

planning = MAX ( 0, replacement houses + ( gap in houses / time to respond to gap ) ) building = Planned Houses / time to plan to buildcompleting = Houses In Construction / time to build housesdemolishing = Houses Completed / average house life

Planned Houses = INTEG( planning - building , planning * time to plan to build )Houses In Construction = INTEG( building - completing , building * time to build houses )Houses Completed = INTEG( completing - demolishing , 5000)

gap in houses = number of houses required - Houses Completedreplacement houses = demolishing

For this tutorial add now this equation :number of houses required = 5000 + STEP ( 50, 10 )


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3. TRUE Houses model structure

The model is adapted to reproduce the mechanism of Vensim.

planning in Vensim, is replaced in TRUE by Planning and TPlanningbuilding in Vensim, is replaced in TRUE by Building and TBuildingcompleting in Vensim, is replaced in TRUE by Completing and TCompletingdemolishing in Vensim, is replaced in TRUE by Demolishing and TDemolishing

Because in Vensim, rates planning, building, completing, demolishing update all together the stocksafter the calculation of flows and variable, chronologies for Tplanning, Tbuilding, Tcompleting,Tdemolishing are set to 10.

Because in Vensim, to simulate continuous mode, TIME STEP = 0.5, value returned by Tplanning should be value of Planning * 0,5 ( or Planning * 1/ 2, or Planning / 2 ).It is the same mechanism for Tbuilding, Tcompleting, Tdemolishing.


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II MODEL

A) Create a new empty model Run TRUE software

Create a new empty model : press key : Ctrl+N

B) Save model asSave model as Houses : press key : Ctrl+STape HousesClick on button SaveClick on button No after the question : Save files containing values from compute ?Drag the right tool bar on the left border of the main window, as below :


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C) Setting the date

Setting the date doesn't affect the model, this is only for information.

Let say that the unit of time of the model Adoption is the month :

The date should correspond to month or 15 days, because TIME STEP = 0,5But in this version of TRUE, we can not select month or 15 days.Then you select 1 month for one unit of time, instead month.

Menu View Date setupAfter Cycle, select : Year, tape : 2010 (model starting from year 2010)After Time, select : Month, tape : 1 ( model starting from month 1, January)


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D) Setting the grid

Setting the grid to 20 pixels

Menu View Grid adjustClick on button Select allTape 20 in the field right of the button ApplyClick on the button ApplyClick on the button Ok

Enable the grid

Menu View Grid enable


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III FRAME

A) Create new frame

Creating frame doesn't affect the model, this is only for display.

Click on the button Frame of the tool bar Click in the black background of the windowPress the key Escape, or right-click the mouse


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B) Setting the new frame

Rename the new frame :

Click on the title bar of the framePress key F2Tape Houses then press key Enter

Resize the frame Houses :

Click on the right-bottom handle of the frameDrag this handle to resize the frame

Enable option move the element:

Right-click on the title of the frameSelect the option Enable : move the elements

so, when you move the frame ( dragging its title bar ) , the elements inside will be moved too

Create another frame and rename it Parameters:


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C) Customize frames

Right-click on the title of the frameSelect the option Specific colourClick on the coloured rectangle of the line Background colourSelect colour, click on buttons Apply... and Close


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Frames of the model Houses


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IV STOCKS

Stocks are called objects in TRUE software.Stocks can be used as constant variable when no flows link them.

A) Create stocks

1. Create stocks used as constant variables

Click on the button Object of the tool bar Click in the frame Parameters 4 times as below :Press the key Escape or right-click the mouse

By default, the names of the stocks are O, O[1], O[2], O[3] Object, object 1, ...


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2. Setting the new stocks

Rename the stock O and initialise its dotation :The dotation is the first and initial value of the stock, for time = 0

Click on the stock OPress key F2 (or F3)Tape time to respond/to gap the char / allows to split the name when displayed in modelTape in the field Dotation : 8

press key Enter or click on button OK

3. Rename and initialise the stocks Note : the char / allows to split the name when displayed in model

stock O[1] time to plan/to build, dotation = 3stock O[2] time to build/houses, dotation = 6stock O[3] average/house life, dotation = 1200


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4. Create stocks updated by flows

Click on the button Object of the tool bar Click in the frame Houses 5 times as below :Press the key Escape or right-click the mouse

5. Rename and initialise the stocks

Note : the char / allows to split the name when displayed in model

stock O -Planned/Houses, dotation = 0stock O[1] Planned/Houses, dotation = 12,5stock O[2] Houses in/Construction, dotation = 25stock O[3] Houses/Completed, dotation = 5000stock O[4] Houses/Demolished, dotation = 0


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Houses Completed dotation explanation :

Why Houses Completed dotation = 5000 ?

Vensim equation is :Houses Completed = INTEG( completing - demolishing , 5000 )

Then Houses Completed dotation = 5000

Planned Houses dotation explanation :

Why Planned Houses dotation = 12,5 ?

Vensim equation is :Planned Houses = INTEG( planning - building , planning * time to plan to build )Initial value = planning * time to plan to buildwith time to plan to build = 3and: planning = MAX ( 0, replacement houses + ( gap in houses / time to respond to gap ) )

gap in houses = number of houses required - Houses Completed

gap in houses = (5000 5000) = 0

replacement houses = demolishingdemolishing = Houses Completed / average house lifedemolishing = 5000 / 1200 = 4,1666666replacement houses = 4,166666

planning = 4,166666

Then :Planned Houses dotation = planning * time to plan to build = 4,1666666 * 3 = 12,499999 = 12,5

Houses in Construction dotation explanation :

Why Houses In Construction dotation = 25 ?

Vensim equation is :Houses In Construction = INTEG( building - completing , building * time to build houses )Initial value = building * time to build houses with time to build houses = 6and building = Planned Houses / time to plan to buildwith time to plan to build = 3

Planned Houses = INTEG( planning - building , planning * time to plan to build )Planned Houses (dotation) = 12,5 ( see below)

building = (12,5 / 3) = 4,166666

Then :Houses In Construction dotation = building * time to build houses

= 4,1666666 * 6 = 24,999999 = 25


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Stocks with dotations


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V FLOWS

Flow that links two stocks is called link in TRUE software.Flow that doesn't link two stocks is called virtual link in TRUE software.

A) Create links

Click on the button Link of the tool bar Click on the stock -Planned Houses :Click on the stock Planned HousesPress the key Escape, or right-click the mouse

By default, the names of the links are L, L[1]] Link, Link 1,

1. Rename the link L :

Click on the link LPress key F2Tape TPlanning and press key enter


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2. Editing the link TPlanning :

Click on the link TPlanningPress key F3

The window Link display the list of actions of the link TPlanning :

By default, one action is created.

TRUE default temporal parameters are :

- Chronology = 1- Start = 1- Interval = 1- Repeat = 12

That means that the action will be executed starting from time one, every one time, 12 times.According the setting date where time is month, this action will be executed every month of everyyear.

Note that cycle is year in this case.

Note that the cell of the column Ed is red, that means that the action is in editing mode, in the window1 Actions : TPlanning .... .

To learn more about this window see Manual Part 05 - Actions


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3. Setting the temporal parameters of the action of the link TPlanning

According Time Bounds from Vensim Houses model below :

INITIAL TIME = 0FINAL TIME = 100TIME STEP = 0.5 ( continuous time simulation )Units for Time : Month

Continuous time simulation

Setting the default temporal parameters of the TRUE House model as following : because TIME STEP = 0,5 we should calculate the model for (100 x 2) units of timeand we should divide by 2 the value transferred between two stocks.

- Chronology = 1- Start = 1- Interval = 1- Repeat = 12

If necessary modify the parameters, for example : Repeat to 12 : column Repeat = 12

Click twice on the cell Repeat of the line of the actionTape 12

To save, click on the black background of the model and on the button Save action if this window.

Temporality of the model : default cycle

With those temporal parameters the default cycle contains 12 units of time : 1 from 12.The model can be then executed for 20 cycles, without changing this temporal parameters,so it will be computed for 20 x 12 = 240 units of time.


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4. Set the default temporal parameters

Set the current temporal parameters as the default temporal parameters for next actions to be created :

Right-click on the line of the actionSelect option Parameters as default

Note that in Vensim software :

There are no temporal parameters.All flows and variables are calculated for every unit of time.The order of calculation is automatic.

Note that in TRUE software :

Temporal parameters define executing units of time for each action.Executing order of each action is defined by chronology parameter.


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5. Create the 3 following links as below

link TBuilding between Stocks Planned Houses and Houses In Constructionlink TCompleting between Stocks Houses In Construction and Houses Completedlink TDemolishing between Stocks Houses Completed and Houses Demolished

Note that the default chronologies (set to 1) of the actions are displayed above the links.


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B) Create virtual links

Click on the button Link of the tool bar Click in the frame Houses 7 times as belowPress the key Escape, or right-click the mouse

By default, the names of the virtual links are Lv, Lv[1], Lv[2] Virtual link, Virtual link 1, ...

1. Rename virtual links

Rename the link Lv :

Click on the link LvPress key F2Tape Planning and press key enter

Rename the other links as below : Note : the char / allows to split the name when displayed in model

virtual link Lv[1] Building

virtual link Lv[2] Completingvirtual link Lv[3] gap in housesvirtual link Lv[4] number of/houses /requiredvirtual link Lv[5] replacement/housesvirtual link Lv[6] Demolishing


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Virtual links


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C) Setting the chronologies

We need set the chronologies of the actions to define their order of execution.

1. Chronologies of the actions of the links which update the stocks

In Vensim, the stocks are updated after calculation of all variables and flows in the model.

Then in this TRUE model, we can set the chronologies of the links which update stocks to 10 :

Click on the link TPlanningPress key F3Click twice on the cell Chr of the line of the actionTape 10

To save, click on the black background of the model and on the button Save action if this window.

Repeat this setting for TBuilding Tcompleting and TDemolishing


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2. Chronologies of the actions of the virtual links

In Vensim, we can't see the chronologies of the actions because they are automatic.Then, we have to deduct them observing the Vensim House model.To do that, number from 1 to n, the flows and the variables behind arrows starting from stocks to rates.

Set the chronologies for the actions of the links of this model as below :

Planning 4Building 2Completing 2Demolishing 2gap in house 3number of houses required 2replacement houses 3


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D) Editing the procedures of the actions of the links

We should write the equations of the procedures of the actions of the links.

1. Equation of the action of the link TPlanning

Click on the link TPlanningPress key F3

The window 1 Action : Tplanning is now opened :

To learn more about this window see Manual Part 05 - Actions

In this window replace the code by this equation :

y = Lvalue ( "Planning" ) / 2

You can too drag and drop the link Planning in this window instead taping the codeLvalue ( "Planning" )

The function Lvalue() returns the current value of one link.The return value of the action is the variable y ( currency type).

Click on the button Save or press key : Ctrl+SClick on the button Exit or press key : Escape


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The two stocks -Planned Houses and Planned Houses will be updated with the return value ycalculated by this code.

Because TIME STEP = 0,5 we divide by 2 the value to be transferred between this stocks, to simulate thecontinuous simulation mode.

2. Equations of the actions of the other link s

Edit the actions of the links as following :

Tbuilding y = Lvalue ( "Building" ) / 2Tcompleting y = Lvalue ( "Completing" ) / 2TDemolishing y = Lvalue ( "Demolishing" ) / 2


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E) Editing the procedures of the actions of the virtual links

We should write the equations of the procedures of the actions of the virtual links.

1. Equation of the actions of the virtual links

Write this following code in the windows of the actions of the virtual links : Note : The function Ovalue() returns the current value of one stock. Note : The function Lvalue() returns the current value of one flow.Note : the char / allows to split the name when displayed in model.

Planninggx , gm, y1 , y2 , y3 is a currencyy1 = Lvalue ( "replacement/houses" )y2 = Lvalue ( "gap in houses" )y3 = Ovalue ( "time to respond/to gap" )gm = y1 + ( y2 / y3 )y = Max ( 0 , gm)

Buildingy1 , y2 are currencyy1 = Ovalue ( "Planned/Houses" )y2 = Ovalue ( "time to plan/to build" )y = y1 / y2

Completingy1 , y2 are currencyy1 = Ovalue ( "Houses in/Construction" )y2 = Ovalue ( "time to build/houses" )y = y1 / y2

Demolishingy1 , y2 are currenciesy1 = Ovalue ( "Houses/Completed" )y2 = Ovalue ( "average/house life" )y = y1 / y2

gap in housesy1 , y2 are currencyy1 = Lvalue ( "number of/houses/required" )y2 = Ovalue ( "Houses/Completed" )y = y1 - y2

number of houses requiredy = 5000IF nbt > 20 THEN y = 5050//Simulates the function STEP(height,stime) STEP(50,20)//the function returns 5000 for t=20, it returns 5050//nbt is the counter of unit of time for all cycles//t is the counter of unit of time in one cycle

replacement housesy = Lvalue ( "Demolishing" )


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VI COMPUTE THE MODEL

Note that the blue button Compute, under menu View, is enable after creating the first stock.If this button is enable, that means that the model is modified and you have to compute it, first or again.

A) Compute the model for one cycle

Click on the blue button Compute

While computing, the button is red and a progress bar is displayed :

After computing, the button is blue and disable.


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VIII DISPLAY THE MODEL

A) Display the values of the model after computing

After computing, values of the stocks and flows are displayed, according the selected unit of timesSelect the unit of time using blue cursors,or with buttons Date of the top tool-bar,or with the key left or right

To learn more see Manual Part 02 Model chapter VIII

IX DISPLAY VALUES IN TABLE

Display values in table and compare them with those of Vensim Houses modelOpen the example 09 Houses_from_Vensim_en.Check values.

To be continued.


Manual Part 00 - Tutorial 02.pdf

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