Difference between revisions of "OpenModelica/C2/Array-Functions-and-Operations/English"
(Created page with "{| border=1 ||'''Visual Cue''' ||'''Narration''' |- || Slide: '''Title Slide''' || Welcome to the Spoken Tutorial on '''Array Functions and Operations'''. |- || Slide: '''...") |
|||
(4 intermediate revisions by 2 users not shown) | |||
Line 16: | Line 16: | ||
* how to use '''OMShell''' | * how to use '''OMShell''' | ||
− | |||
* how to use '''array construction functions'''. | * how to use '''array construction functions'''. | ||
* how to perform '''arithmetic operations''' on '''vectors''' and '''matrices'''. | * how to perform '''arithmetic operations''' on '''vectors''' and '''matrices'''. | ||
− | * how to use '''conversion functions'''. | + | * how to use '''array conversion functions'''. |
|- | |- | ||
Line 41: | Line 40: | ||
* knowledge of '''function''' and '''array declaration''' in '''Modelica'''. | * knowledge of '''function''' and '''array declaration''' in '''Modelica'''. | ||
* Prerequisite tutorials are mentioned on our website. | * Prerequisite tutorials are mentioned on our website. | ||
+ | * Please go through them. | ||
|- | |- | ||
Line 46: | Line 46: | ||
'''OMShell''' | '''OMShell''' | ||
− | || '''OMShell''' | + | || Let us learn more about '''OMShell''' now. |
− | + | *'''OMShell''' is an interactive command line tool. | |
− | It | + | *It is a part of '''OpenModelica'''. |
− | '''Functions''' can also be called in '''OMShell'''. | + | *'''OpenModelica compiler''' can be invoked using '''commands''' typed in '''OMShell'''. |
+ | |||
+ | *It can be used for loading '''classes''' and simulating them. | ||
+ | |||
+ | *'''Functions''' can also be called in '''OMShell'''. | ||
|- | |- | ||
− | || | + | || Narration |
− | || We shall now use '''classes''' named '''polynomialEvaluatorUsingVectors''' and '''functionTester''' to demonstrate OMShell. | + | || We shall now use '''classes''' named '''polynomialEvaluatorUsingVectors''' and '''functionTester''' to demonstrate '''OMShell'''. |
− | These '''classes''' were discussed in | + | These '''classes''' were discussed in previous tutorials. |
− | For more information on these '''classes''', please watch the prerequisite tutorials. | + | |- |
+ | ||Narration | ||
+ | ||For more information on these '''classes''', please watch the prerequisite tutorials. | ||
+ | |||
+ | |- | ||
+ | ||Narration | ||
+ | ||All the '''commands''' to be used in this tutorial are provided in a file named '''OMShell-commands.txt'''. | ||
− | |||
You may locate and download all the '''code files''' available on our website. | You may locate and download all the '''code files''' available on our website. | ||
Line 70: | Line 79: | ||
|- | |- | ||
|| Click on '''Search''' icon in '''Icon Tray'''. | || Click on '''Search''' icon in '''Icon Tray'''. | ||
− | || | + | || Now let me launch '''OMShell'''. |
− | To open '''OMShell''' on '''Ubuntu''' Operating System, | + | To open '''OMShell''' on '''Ubuntu''' Operating System, click on '''Dash Home''' icon at top left in the launcher. |
− | + | ||
− | + | ||
|- | |- | ||
− | || Type '''OMShell''' | + | || Type '''OMShell''' >> click on '''OMShell''' icon |
− | || Type '''OMShell''' in the | + | || Type '''OMShell''' in the search bar. |
+ | |||
Click on '''OMShell''' icon. | Click on '''OMShell''' icon. | ||
− | In '''Windows''', you may find | + | |- |
+ | || | ||
+ | ||In '''Windows''', you may find the icon in '''Start''' menu. | ||
|- | |- | ||
|| /* OMShell */ | || /* OMShell */ | ||
− | || | + | || Now, let us learn a few useful commands. |
− | |||
− | + | Firstly, go to the location where you saved the text file named '''OMShell-commands.txt''' and open it. | |
− | |||
− | |||
− | |||
Note that this file has all the '''commands''' to be used in this tutorial. | Note that this file has all the '''commands''' to be used in this tutorial. | ||
Line 100: | Line 106: | ||
Hence, you may refer to this file whenever in doubt. | Hence, you may refer to this file whenever in doubt. | ||
− | + | |- | |
+ | ||Switch to '''OMShell''' | ||
+ | ||Now let me switch to '''OMShell'''. | ||
|- | |- | ||
Line 111: | Line 119: | ||
|| | || | ||
|| This prints the path to current directory. | || This prints the path to current directory. | ||
+ | |||
+ | |- | ||
+ | || | ||
+ | || Now let us change current directory to the location where you have saved the '''code files'''. | ||
|- | |- | ||
|| Type // '''cd(“path”)''' // | || Type // '''cd(“path”)''' // | ||
− | || | + | || Let me change directory on my system. |
− | + | Type '''cd'''(open and close parentheses) (within double quotes), specify the path. | |
− | + | Press '''Enter'''. | |
− | + | ||
− | + | ||
|- | |- | ||
|| | || | ||
− | || Note that a '''Windows''' path uses '''forward slash''' unlike the '''backward slash''' in '''Ubuntu'''. | + | || Note that a '''Windows''' path uses '''forward slash''' unlike the '''backward slash''' used in '''Ubuntu'''. |
'''Windows''' users need to be cautious of this fact. | '''Windows''' users need to be cautious of this fact. | ||
Line 130: | Line 140: | ||
|- | |- | ||
|| Type // '''loadFile(“polynomialEvaluatorUsingVectors.mo”) '''// | || Type // '''loadFile(“polynomialEvaluatorUsingVectors.mo”) '''// | ||
− | || | + | || Now let us load '''polynomialEvaluatorUsingVectors''' function. |
− | Type '''loadFile (within parentheses) (within double quotes)'''. | + | Type '''loadFile''' (within parentheses) (within double quotes) '''polynomialEvaluatorUsingVectors.mo'''. |
− | + | |- | |
+ | ||Highlight | ||
+ | ||Note that '''F''' is upper-case in '''loadFile()''' command. | ||
− | + | |- | |
+ | ||Press '''Enter''' | ||
+ | ||This command can be used to load '''class''' or '''model''' files with a file extension of '''.mo'''. | ||
− | + | Now press '''Enter'''. | |
|- | |- | ||
Line 146: | Line 160: | ||
|- | |- | ||
|| Type // '''polynomialEvaluatorUsingVectors(10) //''' | || Type // '''polynomialEvaluatorUsingVectors(10) //''' | ||
− | || | + | || Now let us call this function interactively. |
− | Type '''polynomialEvaluatorUsingVectors (with an argument of) 10'''. | + | Type '''polynomialEvaluatorUsingVectors''' (with an argument of) '''10'''. |
Press '''Enter'''. | Press '''Enter'''. | ||
Line 157: | Line 171: | ||
|- | |- | ||
− | || Type // '''loadFile(“functionTester.mo”) '''// | + | || Type // '''loadFile(“functionTester.mo”) '''// >> Press '''Enter''' |
− | || Let me load '''functionTester''' | + | || Let me now load '''functionTester class'''. |
− | Type '''loadFile(functionTester.mo | + | Type '''loadFile''' (open and close parentheses) (within double quotes) '''functionTester.mo'''. |
+ | |||
+ | Press '''Enter'''. | ||
|- | |- | ||
− | || Type // '''simulate(functionTester,startTime=0,stopTime=1) '''// | + | || Type // '''simulate(functionTester,startTime=0,stopTime=1) '''// >> Press '''Enter''' |
− | || | + | || Now let us simulate '''functionTester class'''. |
− | Type '''simulate (within | + | Type '''simulate''' (within parentheses) '''functionTester''' (comma) '''startTime''' (equals) '''0 stopTime''' (equals) '''1'''. |
+ | |||
+ | Press '''Enter'''. | ||
|- | |- | ||
|| | || | ||
− | || The simulation is complete. | + | || The simulation is now complete. |
− | Let us plot variable '''z''' from '''functionTester class. | + | |- |
+ | || | ||
+ | ||Let us plot variable '''z''' from '''functionTester''' class. | ||
|- | |- | ||
− | || Type // '''plot({z}) '''// | + | || Type // '''plot({z}) '''// >> press '''Enter''' |
− | || Type '''plot (within parentheses) (within curly braces) z''' and press '''Enter'''. | + | || Type '''plot''' (within parentheses) (within curly braces) '''z''' and press '''Enter'''. |
− | This generates a plot of variable '''z''' vs '''time'''. | + | This command generates a plot of variable '''z''' vs '''time'''. |
|- | |- | ||
− | || | + | || Back to the slides |
− | || | + | || Now let me go back to the slides. |
|- | |- | ||
Line 194: | Line 214: | ||
|| '''Array construction functions''' are used to construct '''arrays''' of given size. | || '''Array construction functions''' are used to construct '''arrays''' of given size. | ||
+ | |||
Now let us take a look at a few '''array construction functions'''. | Now let us take a look at a few '''array construction functions'''. | ||
Line 199: | Line 220: | ||
We will also practice them using '''OMShell'''. | We will also practice them using '''OMShell'''. | ||
− | '''fill()''' is used to | + | *'''fill()''' is function used to create an '''array''' with all the elements same. |
− | The syntax for '''fill''' is as shown. | + | :The syntax for '''fill''' is as shown. |
− | First '''argument''' represents the number which fills the '''array'''. | + | *First '''argument''' represents the number which fills the '''array'''. |
− | Remaining '''arguments''' represent the size of each dimension | + | *Remaining '''arguments''' represent the size of each dimension. |
− | '''zeros()''' | + | *'''zeros()''' is a function used to create an '''array''' filled with zeros. |
− | Syntax for '''zeros()''' function is as shown. | + | :Syntax for '''zeros()''' function is as shown. |
− | '''Arguments''' represent the size of each dimension. | + | *'''Arguments''' represent the size of each dimension of the array. |
− | '''identity()''' function creates an identity matrix. | + | *'''identity()''' function creates an identity matrix. |
− | It takes one '''argument''' that represents the size of both dimensions. | + | :It takes one '''argument''' that represents the size of both dimensions. |
|- | |- | ||
− | || | + | || Back to '''OMShell''' |
− | || | + | || Now let me demonstrate these functions using '''OMShell'''. |
+ | |||
Let me go back to '''OMShell'''. | Let me go back to '''OMShell'''. | ||
Line 227: | Line 249: | ||
Type // '''fill(5,2,2)''' // | Type // '''fill(5,2,2)''' // | ||
− | || Type '''fill(within parentheses) 5 (comma) 2 (comma) 2'''. | + | || Type '''fill'''(within parentheses)''' 5''' (comma) '''2''' (comma) '''2'''. |
− | This command generates a two by two matrix with all its elements '''5'''. | + | This command generates a two by two matrix with all its elements being '''5'''. |
− | The first arguments represents element to be filled. | + | The first '''arguments''' represents the element to be filled within the '''array'''. |
− | + | '''2''' represents the size of first dimension. | |
− | + | and the third argument '''2''', represents the size of second dimension. | |
|- | |- | ||
− | || | + | ||Press '''Enter''' |
− | || | + | ||Now press '''Enter'''. |
|- | |- | ||
− | || | + | ||Result shown on screen |
− | || | + | ||The result is as expected. |
− | + | Elements with one set of curly braces represent a row. | |
− | The result is as expected. | + | Hence this matrix has two rows and two columns. |
+ | |||
+ | |- | ||
+ | || Type // '''zeros(2,2)''' // >> press '''Enter'''. | ||
+ | || Now let us use '''zeros() function''' to create a (two by two) matrix with all its elements '''zero'''. | ||
+ | |||
+ | Type '''zeros''' (within parentheses) '''2''' (comma) '''2''' and press '''Enter'''. | ||
+ | |||
+ | |- | ||
+ | ||Result shown on screen | ||
+ | ||The result is as expected. | ||
|- | |- | ||
|| Type // '''identity(3)''' // | || Type // '''identity(3)''' // | ||
− | || Let us now try '''identity''' | + | || Let us now try '''identity function'''. |
− | Type '''identity(3) | + | Type '''identity(3)'''. |
− | + | This creates an '''identity''' matrix which is '''3''' (by) '''3''' in its size. | |
|- | |- | ||
|| | || | ||
|| We can also perform '''arithmetic operations''' and use '''assignment statements''' in '''OMShell'''. | || We can also perform '''arithmetic operations''' and use '''assignment statements''' in '''OMShell'''. | ||
+ | |||
+ | Let us create two matrices and perform '''arithmetic operations''' on them. | ||
|- | |- | ||
− | || Type // '''a:=[1,2;3,4] '''// | + | || Type // '''a:=[1,2;3,4] '''// >> press '''Enter''' |
− | || | + | || Type '''a''' (colon) (equals) (within square brackets) '''1''' (comma) '''2''' (semicolon) '''3''' (comma) '''4'''. |
− | + | *'''Comma''' is used to separate elements in a row | |
+ | *whereas '''semi-colon''' is used to separate rows themselves. | ||
− | ''' | + | Now press '''Enter'''. |
|- | |- | ||
− | || Type // '''b:=identity(2) '''// | + | || Type // '''b:=identity(2) '''// >> press '''Enter''' |
− | || Type '''b (colon) (equals) identity ( | + | || Type '''b''' (colon) (equals) '''identity (2)'''. |
+ | |||
+ | This generates a '''2 by 2 identity''' matrix. | ||
|- | |- | ||
− | || Type // '''a + b '''// | + | || Type // '''a + b '''// >> press '''Enter''' |
− | || Type '''a (plus) b''' and press '''Enter'''. | + | || Now let us perform '''arithmetic operations''' on '''a''' and '''b'''. |
+ | |||
+ | Type '''a''' (plus) '''b''' and press '''Enter'''. | ||
This performs matrix addition. | This performs matrix addition. | ||
|- | |- | ||
− | || Type // '''a * b''' // | + | || Type // '''a * b''' // >> press '''Enter''' |
− | || Type '''a (asterisk) | + | || Type '''a''' (asterisk)''' b'''. |
This performs matrix multiplication. | This performs matrix multiplication. | ||
− | |||
− | |||
− | |||
− | |||
Press '''Enter'''. | Press '''Enter'''. | ||
+ | |||
+ | |- | ||
+ | || Type // '''a .* b''' // >> press '''Enter''' | ||
+ | || Type '''a''' (dot) (asterisk) '''b''' and press '''Enter'''. | ||
This performs element-wise multiplication of the two matrices. | This performs element-wise multiplication of the two matrices. | ||
Line 298: | Line 337: | ||
|- | |- | ||
− | || | + | ||Back to the slides |
− | || | + | || Now let me switch back to the slides. |
|- | |- | ||
Line 305: | Line 344: | ||
'''Reduction Functions''' | '''Reduction Functions''' | ||
− | || '''Reduction functions''' take | + | || '''Reduction functions''' take '''array''' as '''input''' and return '''scalar''' as '''output'''. |
− | '''min()''' function returns the | + | '''min()''' is a '''function''' which returns the smallest value in an '''array'''. |
− | '''max()''' | + | Similarly, '''max() function''' returns the largest value in an '''array'''. |
− | '''sum()''' | + | '''sum()''' returns the sum of all elements |
− | '''product()''' | + | and '''product()''' returns the product of all elements. |
|- | |- | ||
− | || | + | ||Switch to '''OMShell''' |
|| Let me switch to '''OMShell''' to demonstrate these functions. | || Let me switch to '''OMShell''' to demonstrate these functions. | ||
|- | |- | ||
|| '''x = [3,4;5,6]''' | || '''x = [3,4;5,6]''' | ||
− | || Let me create a new matrix | + | || Let me create a new matrix. |
− | + | '''x (colon)(equals) (within square brackets) 3 (comma) 4 (semicolon) 5 (comma) 6'''. | |
|- | |- | ||
− | || Type // '''min(x)''' // | + | || Type // '''min(x)''' // >> press '''Enter''' |
− | + | || Type '''min (x)''' to obtain the minimum value of '''x'''. | |
− | + | ||
− | Type '''min ( | + | |
− | + | ||
− | + | ||
|- | |- | ||
− | || Type // '''max(x)''' // | + | || Type // '''max(x)''' // >> press '''Enter''' |
− | || Type '''max ( | + | || Type '''max (x)''' to obtain the largest value in array '''x'''.. |
− | + | ||
− | + | ||
|- | |- | ||
− | || Type // '''sum(x) '''// | + | || Type // '''sum(x) '''// >> press '''Enter''' |
− | + | || Similarly type '''sum (x)''' to obtain the sum of all elements. | |
− | + | ||
− | + | ||
− | + | ||
− | + | ||
|- | |- | ||
− | || Type // '''product(x)''' // | + | || Type // '''product(x)''' // >> press '''Enter''' |
− | + | || and '''product (x)''' to obtain the product of individual elements min array '''x'''. | |
− | + | ||
− | + | ||
− | + | ||
− | + | ||
|- | |- | ||
− | || | + | || Back to the slides |
− | || Let me go back to the slides. | + | || Let me go back to the slides once again. |
|- | |- | ||
Line 363: | Line 388: | ||
'''Miscellaneous functions''' | '''Miscellaneous functions''' | ||
− | || Let us now discuss various other functions that take an '''array''' as '''input'''. | + | || Let us now discuss various other '''functions''' that take an '''array''' as '''input'''. |
− | '''abs()''' is a function | + | *'''abs()''' is a '''function''' which returns an '''array''' with the '''absolute values''' of all its elements. |
− | '''size()''' returns a vector with the size of each dimension. | + | *'''size()''' returns a vector with the size of each dimension. |
− | '''ndims()''' | + | *'''ndims()''' returns the number of dimensions in an array. |
|- | |- | ||
− | || | + | || '''Summary Slide''' |
|| This brings us to the end of this tutorial. | || This brings us to the end of this tutorial. | ||
In this tutorial, we used '''OMShell''' to interactively demonstrate '''array functions'''. | In this tutorial, we used '''OMShell''' to interactively demonstrate '''array functions'''. | ||
− | These functions are part of '''Modelica''' language specification. | + | These '''functions''' are part of '''Modelica''' language specification. |
Hence, they may be used while writing '''classes''' in '''OMEdit''' as well. | Hence, they may be used while writing '''classes''' in '''OMEdit''' as well. | ||
Line 385: | Line 410: | ||
'''Assignment''' | '''Assignment''' | ||
− | || As an assignment, apply '''abs(), | + | || As an assignment, apply '''abs(), '''ndims()''' and '''size() functions''' to an '''array'''. |
− | Secondly, we have used a two-dimensional array or matrix as an argument to most of the functions. | + | Secondly, we have used a '''two-dimensional array''' or matrix as an '''argument''' to most of the '''functions'''. |
− | As an assignment, implement all these functions with | + | As an assignment, implement all these '''functions''' with '''three-dimensional arrays'''. |
− | + | ||
− | + | ||
− | + | ||
− | + | ||
|- | |- | ||
Line 399: | Line 420: | ||
About the '''Spoken Tutorial project''' | About the '''Spoken Tutorial project''' | ||
− | || Watch the video available at the link | + | || Watch the video available at the following link: |
[http://spoken-tutorial.org/ http][http://spoken-tutorial.org/ ://][http://spoken-tutorial.org/ spoken][http://spoken-tutorial.org/ -][http://spoken-tutorial.org/ tutorial][http://spoken-tutorial.org/ .][http://spoken-tutorial.org/ org] /What\_is\_a\_Spoken\_Tutorial | [http://spoken-tutorial.org/ http][http://spoken-tutorial.org/ ://][http://spoken-tutorial.org/ spoken][http://spoken-tutorial.org/ -][http://spoken-tutorial.org/ tutorial][http://spoken-tutorial.org/ .][http://spoken-tutorial.org/ org] /What\_is\_a\_Spoken\_Tutorial | ||
+ | |||
+ | Its summarises the '''Spoken Tutorial''' project. | ||
|- | |- | ||
Line 417: | Line 440: | ||
'''Forum to answer questions''' | '''Forum to answer questions''' | ||
− | || If you have questions in this tutorial, please visit the webpage mentioned. | + | || If you have questions in this spoken tutorial, please visit the webpage mentioned. |
|- | |- | ||
Line 423: | Line 446: | ||
'''Textbook Companion Project''' | '''Textbook Companion Project''' | ||
− | || We coordinate coding of solved examples | + | || We coordinate coding of solved examples of popular books. |
− | + | Please contact us. | |
− | + | ||
− | Please | + | |
|- | |- | ||
Line 433: | Line 454: | ||
'''Lab Migration Project''' | '''Lab Migration Project''' | ||
− | || We help migrate | + | || We help migrate commercial simulator labs to '''OpenModelica'''. |
|- | |- | ||
Line 439: | Line 460: | ||
'''Acknowledgements''' | '''Acknowledgements''' | ||
− | || '''Spoken Tutorial Project''' is | + | || '''Spoken Tutorial Project''' is funded by '''NMEICT, MHRD''' Government of India. |
|- | |- | ||
Line 445: | Line 466: | ||
'''Thanks''' | '''Thanks''' | ||
− | || We thank '''OpenModelica''' | + | || We thank the development team of '''OpenModelica''' for their support. |
− | + | ||
− | + | ||
− | + | ||
− | + | ||
− | + | Thank you. |
Latest revision as of 12:31, 22 March 2016
Visual Cue | Narration |
Slide:
Title Slide |
Welcome to the Spoken Tutorial on Array Functions and Operations. |
Slide:
Learning Objectives |
In this tutorial, we are going to learn:
|
Slide:
System Requirements |
To record this tutorial, I am using
Windows users may use any text editor like Notepad instead of gedit. |
Slide:
Prerequisites |
To understand and practice this tutorial, you need
|
Slide:
OMShell |
Let us learn more about OMShell now.
|
Narration | We shall now use classes named polynomialEvaluatorUsingVectors and functionTester to demonstrate OMShell.
These classes were discussed in previous tutorials. |
Narration | For more information on these classes, please watch the prerequisite tutorials. |
Narration | All the commands to be used in this tutorial are provided in a file named OMShell-commands.txt.
Please save all these code files in one directory for easy access. |
Click on Search icon in Icon Tray. | Now let me launch OMShell.
To open OMShell on Ubuntu Operating System, click on Dash Home icon at top left in the launcher. |
Type OMShell >> click on OMShell icon | Type OMShell in the search bar.
|
In Windows, you may find the icon in Start menu. | |
/* OMShell */ | Now, let us learn a few useful commands.
Hence, you may refer to this file whenever in doubt. |
Switch to OMShell | Now let me switch to OMShell. |
Type // cd() // | Type cd open and close parentheses.
Press Enter to display the result produced on execution of the command. |
This prints the path to current directory. | |
Now let us change current directory to the location where you have saved the code files. | |
Type // cd(“path”) // | Let me change directory on my system.
Type cd(open and close parentheses) (within double quotes), specify the path. Press Enter. |
Note that a Windows path uses forward slash unlike the backward slash used in Ubuntu.
Windows users need to be cautious of this fact. | |
Type // loadFile(“polynomialEvaluatorUsingVectors.mo”) // | Now let us load polynomialEvaluatorUsingVectors function.
Type loadFile (within parentheses) (within double quotes) polynomialEvaluatorUsingVectors.mo. |
Highlight | Note that F is upper-case in loadFile() command. |
Press Enter | This command can be used to load class or model files with a file extension of .mo.
Now press Enter. |
// true // | If the file is found, OMShell returns true. |
Type // polynomialEvaluatorUsingVectors(10) // | Now let us call this function interactively.
Type polynomialEvaluatorUsingVectors (with an argument of) 10. Press Enter. |
This command takes an input argument of 10 units and displays the result. | |
Type // loadFile(“functionTester.mo”) // >> Press Enter | Let me now load functionTester class.
Type loadFile (open and close parentheses) (within double quotes) functionTester.mo. Press Enter. |
Type // simulate(functionTester,startTime=0,stopTime=1) // >> Press Enter | Now let us simulate functionTester class.
Type simulate (within parentheses) functionTester (comma) startTime (equals) 0 stopTime (equals) 1. Press Enter. |
The simulation is now complete. | |
Let us plot variable z from functionTester class. | |
Type // plot({z}) // >> press Enter | Type plot (within parentheses) (within curly braces) z and press Enter.
This command generates a plot of variable z vs time. |
Back to the slides | Now let me go back to the slides. |
Slide:
Array Construction Functions
|
Array construction functions are used to construct arrays of given size.
We will also practice them using OMShell.
|
Back to OMShell | Now let me demonstrate these functions using OMShell.
|
/* OMShell */
Type // fill(5,2,2) // |
Type fill(within parentheses) 5 (comma) 2 (comma) 2.
This command generates a two by two matrix with all its elements being 5. The first arguments represents the element to be filled within the array. 2 represents the size of first dimension. and the third argument 2, represents the size of second dimension. |
Press Enter | Now press Enter. |
Result shown on screen | The result is as expected.
Elements with one set of curly braces represent a row. Hence this matrix has two rows and two columns. |
Type // zeros(2,2) // >> press Enter. | Now let us use zeros() function to create a (two by two) matrix with all its elements zero.
Type zeros (within parentheses) 2 (comma) 2 and press Enter. |
Result shown on screen | The result is as expected. |
Type // identity(3) // | Let us now try identity function.
Type identity(3). This creates an identity matrix which is 3 (by) 3 in its size. |
We can also perform arithmetic operations and use assignment statements in OMShell.
Let us create two matrices and perform arithmetic operations on them. | |
Type // a:=[1,2;3,4] // >> press Enter | Type a (colon) (equals) (within square brackets) 1 (comma) 2 (semicolon) 3 (comma) 4.
Now press Enter. |
Type // b:=identity(2) // >> press Enter | Type b (colon) (equals) identity (2).
This generates a 2 by 2 identity matrix. |
Type // a + b // >> press Enter | Now let us perform arithmetic operations on a and b.
Type a (plus) b and press Enter. This performs matrix addition. |
Type // a * b // >> press Enter | Type a (asterisk) b.
This performs matrix multiplication. Press Enter. |
Type // a .* b // >> press Enter | Type a (dot) (asterisk) b and press Enter.
This performs element-wise multiplication of the two matrices. |
Note that it is not necessary to define data-types of variables used in OMShell. | |
Back to the slides | Now let me switch back to the slides. |
Slide:
Reduction Functions |
Reduction functions take array as input and return scalar as output.
min() is a function which returns the smallest value in an array. Similarly, max() function returns the largest value in an array. sum() returns the sum of all elements and product() returns the product of all elements. |
Switch to OMShell | Let me switch to OMShell to demonstrate these functions. |
x = [3,4;5,6] | Let me create a new matrix.
x (colon)(equals) (within square brackets) 3 (comma) 4 (semicolon) 5 (comma) 6. |
Type // min(x) // >> press Enter | Type min (x) to obtain the minimum value of x. |
Type // max(x) // >> press Enter | Type max (x) to obtain the largest value in array x.. |
Type // sum(x) // >> press Enter | Similarly type sum (x) to obtain the sum of all elements. |
Type // product(x) // >> press Enter | and product (x) to obtain the product of individual elements min array x. |
Back to the slides | Let me go back to the slides once again. |
Slide:
Miscellaneous functions |
Let us now discuss various other functions that take an array as input.
|
Summary Slide | This brings us to the end of this tutorial.
In this tutorial, we used OMShell to interactively demonstrate array functions. These functions are part of Modelica language specification. Hence, they may be used while writing classes in OMEdit as well. |
Slide:
Assignment |
As an assignment, apply abs(), ndims() and size() functions to an array.
Secondly, we have used a two-dimensional array or matrix as an argument to most of the functions. As an assignment, implement all these functions with three-dimensional arrays. |
Slide:
About the Spoken Tutorial project |
Watch the video available at the following link:
http://spoken-tutorial.org /What\_is\_a\_Spoken\_Tutorial Its summarises the Spoken Tutorial project. |
Slide:
Spoken Tutorial Workshops |
We conducts workshops using spoken tutorials.
Give certificates. Please contact us. |
Slide:
Forum to answer questions |
If you have questions in this spoken tutorial, please visit the webpage mentioned. |
Slide:
Textbook Companion Project |
We coordinate coding of solved examples of popular books.
Please contact us. |
Slide:
Lab Migration Project |
We help migrate commercial simulator labs to OpenModelica. |
Slide:
Acknowledgements |
Spoken Tutorial Project is funded by NMEICT, MHRD Government of India. |
Slide:
Thanks |
We thank the development team of OpenModelica for their support.
Thank you. |