Nancyvarkey at 15:09, 6 July 2014

2014-07-06T15:09:34Z

Nancyvarkey at 15:07, 6 July 2014

2014-07-06T15:07:13Z

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Tarung at 06:14, 17 June 2014

2014-06-17T06:14:32Z

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Tarung: Created page with ''''Tutorial 3: Developing a Basic model in ASCEND''' {| style="border-spacing:0;" | style="border:0.75pt solid #000001;padding:0.0104in;"| '''Visual Cue''' | s…'

2014-06-15T14:55:42Z

Created page with ''''Tutorial 3: Developing a Basic model in ASCEND''' {| style="border-spacing:0;" | style="border:0.75pt solid #000001;padding:0.0104in;"| <center>'''Visual Cue'''</center> | s…'

New page

'''Tutorial 3: Developing a Basic model in ASCEND'''

{| style="border-spacing:0;"
| style="border:0.75pt solid #000001;padding:0.0104in;"| <center>'''Visual Cue'''</center>
| style="border:0.75pt solid #000001;padding:0.0104in;"| <center>'''Narration'''</center>

|-
| style="border:0.75pt solid #000001;padding:0.0104in;"| Open Slide number 1

Title slide
| style="border:0.75pt solid #000001;padding:0.0104in;"| Welcome to the spoken tutorial on '''Developing a Basic Model in ASCEND'''

|-
| style="border:0.75pt solid #000001;padding:0.0104in;"| Open Slide 2

Learning Objectives
| style="border:0.75pt solid #000001;padding:0.0104in;"| In this tutorial,

We will learn how to

* Build a basic model
* Add methods to the basic model and
* Write dimensionally consistent equations

|-
| style="border:0.75pt solid #000001;padding:0.0104in;"| Open Slide number 3

System Requirement
| style="border:0.75pt solid #000001;padding:0.0104in;"| Here I am using

* Ubuntu Linux OS v. 12.04
* ASCEND v. 0.9.8

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open Slide number 4

Pre-requisites
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| To know more about ASCEND

please visit ascend4.org

For relevant tutorials please visit our website

http://spoken-tutorial.org

|-
| style="border:0.75pt solid #000001;padding:0.0104in;"| Open Slide number 5

Example
| style="border:0.75pt solid #000001;padding:0.0104in;"| Let us begin the tutorial with a simple example. In this example let us solve 3 simultaneous equations with 3 unknowns

we will use a text editor like gedit to write our model

I already have the code for the example in a text file

let me explain the code

|-
| style="border:0.75pt solid #000001;padding:0.0104in;"| Open mymodel.a4c in gedit
| style="border:0.75pt solid #000001;padding:0.0104in;"| Open the file mymodel.a4c in a text editor

|-
| style="border:0.75pt solid #000001;padding:0.0104in;"| Highlight the “system.a4l” line
| style="border:0.75pt solid #000001;padding:0.0104in;"| Initially we mention the library (that is a collection of pre-defined models that we need in our model).

Here we require the basic sysyem.a4l library

.a4l extension denotes the ascend4 library

the name of the library is written in double quotes

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight the semi colon
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| note that semi colon is a statement terminator in ascend

Ascend considers all the statements as one sentence if semi colon is not put after each statement

|-
| style="border:0.75pt solid #000001;padding:0.0104in;"| Highlight MODEL my_model
| style="border:0.75pt solid #000001;padding:0.0104in;"| MODEL my_model begins a model with name my_model

you can give any name to the model

|-
| style="border:0.75pt solid #000001;padding:0.0104in;"| Highlight (*variables declaration*)
| style="border:0.75pt solid #000001;padding:0.0104in;"| In Ascend comments are written in parenthesis enclosed with in a pair of asterik mark

comments are not executed

they make the model easier to understand

we will now define variables for our model

|-
| style="border:0.75pt solid #000001;padding:0.0104in;"| Highlight solver_var

| style="border:0.75pt solid #000001;padding:0.0104in;"| Any variable whose value is expected to be computed by Ascend must be of type solver_var

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight all the defined variables
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Thus we define variable x,y,z,d and a as a solver_var

the definition of the type solver_var is predefined in the system.a4l library

IS_A is an operator in Ascend which is used to define variable types

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight all the equation sequentially
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Equations to be solved are

x+y+z = a*d

x+y+2*z = 5 and

5*x+2*y-3*z = 0

Note that we have not mentioned how to solve this given set of equations

we have also not mentioned which variables are to be specified and which are to be calculated

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight END my_model
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now end this model with END my_model

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Show the loaded model on Ascend interface
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now open this model in Ascend

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight the successful execution line in the message panel
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Note that Ascend has executed the on_load method by default

this can be seen from the message in the panel below

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight the values of the variables on Ascend interface
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Observe that Ascend has given the default value of 0.5 to each of the variable

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Click the solve button
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now click on the solve icon

Ascend displays the results

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight the converged message in the panel below
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| This can be confirmed in the panel below

A converged message is displayed after the successful completion of the calculation

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight the values of the variables y and d
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Note that Ascend squared the system automatically

keeping the values of two variables y and d as default value and calculated the value for rest of the variables

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Right click on d and assign it a value 1

Fix d by selecting the fixed option

Repeat the same for x
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now suppose we want to make x and d as our fixed variable by assigning values to them and solve for a, y and z

then, right click on d and select properties from the drop down menu

Under values, assign a value to d

here I am giving the value 1

now in solving section, select fixed

click on Apply and OK

now similarly repeat the same procedure for fixing the value of x

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight the corresponding results
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| observe that ascend has solve the model and you will have a new set of results

note that the fixed variables are shown in green color and free variables, calculated by Ascend are shown in blue color

Also note that the final result has been displayed with a tick mark and the fixed variables have been denoted by a closed lock icon

we can also specify the fixed and free variables in the code and assigning value to the variables

In Ascend the solution procedure is separate from the problem statement

Methods contain procedures to solve the model

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open my_model in gedit
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| We will now explain different methods to solve our model

open the file my_model.a4c in a text editor

We write the methods after equations

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Delete END my_model and remove asterik from METHODS and end of the code
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now remove the line END my_model

Delete the parenthesis and asterik mark in front of methods and at the end of the code

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlighte the corrsponding lines in the code sequentially
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Under method specify, we fixed variable a and d

we also assign values to the variables as a = 1 and d=3,note that to assign the values to a particular variable, we use a : and = sign together

I will refer := to sign as is equal to from here on

Under method on_load we run the method specify

This is the method that describes Ascend the action to be taken when a model is loaded

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Click on the save button
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now end the method on_load and my_model and save this file

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Show the ascend interface
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now open this with Ascend

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Select the on_load method and run the code
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now under methods select on_load

click on run

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Click on the solve button and highlight the asnwers
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| click on solve icon

observe that Ascend has fixed the variable a and d and calculated the values for x,y and z

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open the code file again in gedit
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now open the code for my_model.a4c again

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Carry out the required editing in the code file
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now remove the values assigned under specify

Now we will add a new method called values

type method values and then type a = 1, d= 2 and end values

now under on_load type run values after run specify

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open the file with ascend
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now save the file and open it with Ascend

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Run the code using on_laod method and press solve
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Again run the method on_load and click on solve

you will see ascend has fixed variable a and d and assigned the values as mentioned under values section in the code

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open the required code file in gedit
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| now let’s look at an interesting feature of dimensional consistency in Ascend with the help of another model

here we will compute the mass of a cylinder

I already have the code for this model

let me explain the code

open cylinder.a4c with a text editor

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight the corresponding line in a sequential order
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| note that here we require atoms.a4l library as compared to systems library used earlier in the last model

atoms is a refined version of systems library

and contains the definition of various variable types

that represent different physical units

For example we write v is a volume

m is a mass etc.

volume, mass etc. are different variable types defined in atoms.a4l

This helps in ensuring that the equations written in Ascend model are dimensionally consistent

After this we write equations and methods as explained earlier

Note that while specifying values for these variable types, we need to mention the corresponding physical units in curly brackets

Here we write V = 100 cm^3 and p = 100kg/m^3

note that V is in CGS units while p is in SI units

The user doesn't have to worry about the units as Ascend itself performs the unit conversion

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open the file in Ascend and run and solve it using the on_load method
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now open this file in Ascend

Now once again run the on_load method

and solve the problem

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight the answers
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| observe that ascend has converted the values of volume into SI units and then calculated the mass in SI units

Note that Ascend by default uses SI units until specified otherwise

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open Slide number 5:

Summary
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Now let us summarize,in this tutorial,

We have learned how to

* Build a basic model
* Add methods to the basic model and
* Write dimensionally consistent equations

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open Slide number 6:

Assignment
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Do the following assignment

Edit the model cylinder in a text editor and make it dimensionally inconsistent

For example, write m is a distance instead of mass

Now run this dimensionally inconsistent model in Ascend and observe the output

Add more variables and equations to the model cylinder.a4c and solve it in Ascend

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open Slide number 7

About the Spoken Tutorial Project
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Information on the spoken tutorial project is available on our website

spoken-tutorial.org

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open Slide number 8

Spoken Tutorial Workshops
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Details on Workshops based on spoken tutorials is also available on the website

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open Slide number 9

Acknowledgements
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Spoken tutorial project is funded by NMEICT,MHRD

|-
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Open Slide number 10

Thank You
| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| This is Priya Bagde from IIT Bombay signing off

Thank You for joining

|}

@@ Line 202: / Line 202: @@
 | style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Highlight the corresponding results
 | style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Observe that '''ASCEND''' has solved the '''model '''and you will have a new set of results.
 Note that the '''fixed variables''' are shown in green color and '''free variables''', calculated by '''ASCEND''' are shown in blue color.
 Also note that the final results has been displayed with a '''tick mark''' and the '''fixed variables''' have been denoted by a '''closed lock icon'''.
 We can also specify the '''fixed''' and '''free variables''' in the '''code''' and assign values to the '''variables'''.
 In '''ASCEND''' the solution procedure is separate from the problem statement.
 '''Methods '''contain procedures to solve the '''model'''.
@@ Line 298: / Line 303: @@
 |-
-| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Run the code using '''on_laod method''' and press '''solve'''
+| style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Run the code using '''on_load method''' and press '''solve'''
 | style="border-top:none;border-bottom:0.75pt solid #000001;border-left:0.75pt solid #000001;border-right:0.75pt solid #000001;padding:0.0104in;"| Again run the '''Method on_load''' and click on '''Solve'''.
 You will see '''ASCEND''' has fixed '''variables a '''and '''d''' and assigned the values as mentioned under '''Values''' section in the '''code'''.
 |-

ASCEND/C2/Writing-basic-model/English - Revision history

Nancyvarkey at 15:09, 6 July 2014

Nancyvarkey at 15:07, 6 July 2014

Tarung at 06:14, 17 June 2014

Tarung: Created page with ''''Tutorial 3: Developing a Basic model in ASCEND''' {| style="border-spacing:0;" | style="border:0.75pt solid #000001;padding:0.0104in;"| '''Visual Cue''' | s…'