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+ | {| border=1 | ||
+ | || '''Time''' | ||
+ | || '''Narration''' | ||
+ | |- | ||
− | + | |00:01 | |
− | + | ||
− | + | ||
− | + | | | Welcome to the spoken tutorial on '''iterative calculations''' using '''Scilab'''. | |
|- | |- | ||
− | |00 | + | | 00:07 |
− | | | | + | | | I am using '''Scilab version 5.2''' in '''Mac operating system''' |
|- | |- | ||
− | | 00 | + | | 00:11 |
− | | | | + | | | but these calculations should work in other versions and also in Scilab that runs in '''Linux''' and '''Windows'''. |
|- | |- | ||
− | | 00 | + | | 00:17 |
− | | | | + | | | I will use the code available in the file 'iteration.sce'. |
|- | |- | ||
− | | 00 | + | |00:22 |
− | | | I | + | || I have opened this file using Scilab editor which I plan to use only as an editor. |
|- | |- | ||
− | |00 | + | | 00:29 |
− | || | + | || Let us create a vector using the colon operator. 'i' is equal to 1 colon 5, |
|- | |- | ||
− | | 00 | + | | 00:38 |
− | || | + | | |creates a vector from 1 to 5, in increments of 1. |
|- | |- | ||
− | | 00 | + | |00:42 |
− | | | | + | | | In this command, 'i' is equal to 1 colon 2 colon 5. |
|- | |- | ||
− | |00 | + | | 00:51 |
− | | | | + | | | We see that the middle argument of 2 indicates the increment. |
|- | |- | ||
− | | 00 | + | | 00:56 |
− | | | | + | | | 1 is the first argument where the vector starts. 'i' cannot go beyond 5, |
|- | |- | ||
− | | | + | | 01:01 |
− | | | | + | | |it can be equal to 5, however. |
|- | |- | ||
− | | 01 | + | | 01:04 |
− | | | | + | | | Note that if the ending argument changes to 6 the result remains the same. |
|- | |- | ||
− | | 01 | + | |01:09 |
− | | | | + | | | It is not difficult to explain this behavior. |
|- | |- | ||
− | |01 | + | |01:13 |
− | | | + | | Can you think for a moment why this happens? |
|- | |- | ||
− | |01 | + | | 01:15 |
− | | | + | |We will now demonstrate the use of the '''for''' statement to perform iterative calculations. |
|- | |- | ||
− | | 01 | + | | 01:22 |
− | + | ||
− | + | ||
− | for i is equal to 1 colon 2 colon 7 disp i end of for loop. | + | |'''for i is equal to 1 colon 2 colon 7 disp i end''' of '''for loop'''. |
|- | |- | ||
− | | 01 | + | | 01:28 |
− | | |I will cut this paste in | + | | |I will cut this, paste in Scilab console, press '''Enter'''. |
|- | |- | ||
− | | 01 | + | | 01:34 |
− | | |This code prints out i | + | | |This code prints out 'i' as we go through the loop. |
|- | |- | ||
− | | 01 | + | | 01:37 |
− | | |The display is due to the command disp - the passed argument is displayed. | + | | |The display is due to the command '''disp''' - the passed '''argument''' is displayed. |
|- | |- | ||
− | | 01 | + | | 01:42 |
− | | |Recall that the for loop is used for integer values. | + | | |Recall that the '''for loop''' is used for integer values. |
|- | |- | ||
− | | 01 | + | | 01:45 |
| | In this case, four integer values, namely, 1, 3, 5 and 7 are displayed. | | | In this case, four integer values, namely, 1, 3, 5 and 7 are displayed. | ||
Line 131: | Line 131: | ||
|- | |- | ||
− | | 01 | + | | 01:50 |
− | | |The number of times the iterations take place is known as priori in for loops. | + | | |The number of times the iterations take place is known as '''priori''' in '''for loops'''. |
|- | |- | ||
− | |01 | + | |01:56 |
| | In the rest of this tutorial, we will stick to the default increment of 1. | | | In the rest of this tutorial, we will stick to the default increment of 1. | ||
Line 143: | Line 143: | ||
|- | |- | ||
− | | 02 | + | | 02:01 |
− | | |Let us begin with the loop that displays i equal to 1 to 5. | + | | |Let us begin with the loop that displays 'i' equal to 1 to 5. |
|- | |- | ||
− | | 02 | + | | 02:10 |
− | | | We will modify this code by introducing the break statement. | + | | | We will modify this code by introducing the '''break''' statement. |
|- | |- | ||
− | |02 | + | |02:18 |
− | | Note that i is displayed only up to 2. | + | | Note that 'i' is displayed only up to 2. |
|- | |- | ||
− | |02 | + | |02:22 |
− | | | The iteration is not carried out till the last value of i, namely | + | | | The iteration is not carried out till the last value of i, namely 5. |
|- | |- | ||
− | |02 | + | |02:27 |
− | | | When i is equal to 2, the if block is executed for the first time. | + | | | When i is equal to 2, the '''if''' block is executed for the first time. |
|- | |- | ||
− | | 02 | + | | 02:30 |
− | | | The break command, however, terminates the loop. | + | | | The '''break''' command, however, terminates the loop. |
|- | |- | ||
− | | 02 | + | | 02:34 |
− | || If we want to get out of a loop when some intermediate condition is satisfied, we can use the break statement. | + | || If we want to get out of a loop when some intermediate condition is satisfied, we can use the '''break''' statement. |
|- | |- | ||
− | | 02 | + | | 02:40 |
| | Note that "i is equal to 2" statement uses the "equal to" sign twice. | | | Note that "i is equal to 2" statement uses the "equal to" sign twice. | ||
Line 191: | Line 191: | ||
|- | |- | ||
− | | 02 | + | | 02:45 |
| | This is the standard way to compare the equality in programming languages. | | | This is the standard way to compare the equality in programming languages. | ||
Line 197: | Line 197: | ||
|- | |- | ||
− | |02 | + | |02:50 |
− | | | The result of this comparison statement is a | + | | | The result of this comparison statement is a '''Boolean: true or false'''. |
|- | |- | ||
− | | 02 | + | | 02:56 |
− | | | We will introduce the continue statement here paste press | + | | | We will introduce the '''continue''' statement here, paste, press '''Enter'''. |
|- | |- | ||
− | | 03 | + | | 03:06 |
− | || This results in i getting displayed only for 4 and 5. | + | || This results in 'i' getting displayed only for 4 and 5. |
|- | |- | ||
− | | 03 | + | | 03:10 |
− | | | For i less than or equal to 3, as given by the i less than or equal to 3 statement, nothing happens. | + | | | For 'i' less than or equal to 3, as given by the i less than or equal to 3 statement, nothing happens. |
|- | |- | ||
− | | 03 | + | | 03:18 |
− | | | The continue statement makes the program skip the rest of the loop. | + | | | The '''continue''' statement makes the program skip the rest of the loop. |
|- | |- | ||
− | | 03 | + | | 03:22 |
− | | Unlike the break statement, however, it does not exit the loop. | + | | Unlike the '''break''' statement, however, it does not exit the loop. |
|- | |- | ||
− | | 03 | + | | 03:25 |
− | | | The parameter i is incremented and all the calculations of the loop are executed for the new i. | + | | | The parameter 'i' is incremented and all the calculations of the loop are executed for the new i. |
|- | |- | ||
− | | 03 | + | | 03:32 |
− | | | We take a small break and show how to get help for operators of the type less than or equal to. | + | | | We take a small break and show how to get help for operators of the type 'less than or equal to' (<=). |
|- | |- | ||
− | | 03 | + | | 03:38 |
− | | |Let us type less than or equal to with help | + | | |Let us type 'less than or equal to with help'. |
|- | |- | ||
− | | 03 | + | | 03:46 |
− | || This opens the | + | || This opens the Scilab '''Help Browser'''. |
|- | |- | ||
− | | 03 | + | | 03:51 |
− | || We see that the help is available under the option less. | + | || We see that the help is available under the option '''less'''. |
|- | |- | ||
− | | 03 | + | | 03:56 |
− | | | So now after closing this we type help less | + | | | So now after closing this, we type '''help less'''. |
|- | |- | ||
− | |04 | + | |04:06 |
− | || We see the required help instructions here. I will close this. | + | || We see the required '''help''' instructions here. I will close this. |
|- | |- | ||
− | |04 | + | |04:11 |
− | | | The for statement in Scilab is more powerful than in programming languages. | + | | | The '''for''' statement in Scilab is more powerful than in programming languages. |
|- | |- | ||
− | | 04 | + | | 04:16 |
− | | | For example, let us perform a loop over a vector: | + | | | For example, let us perform a '''loop''' over a '''vector''': |
|- | |- | ||
− | | 04 | + | | 04:24 |
− | | | This script displays all values of v. | + | | | This script displays all values of 'v'. |
|- | |- | ||
− | | 04 | + | | 04:28 |
| | Until now we have been displaying only the variables. | | | Until now we have been displaying only the variables. | ||
Line 299: | Line 299: | ||
|- | |- | ||
− | | 04 | + | | 04:32 |
| | We can indeed display the result of a calculation as well. | | | We can indeed display the result of a calculation as well. | ||
Line 305: | Line 305: | ||
|- | |- | ||
− | | 04 | + | | 04:35 |
| | The following code displays the square of the numbers. | | | The following code displays the square of the numbers. | ||
Line 311: | Line 311: | ||
|- | |- | ||
− | |04 | + | |04:44 |
− | | | We have spent quite a bit of time explaining the for loop. | + | | | We have spent quite a bit of time explaining the '''for loop'''. |
|- | |- | ||
− | | 04 | + | | 04:48 |
− | | | Let us now move on to the while loops. | + | | | Let us now move on to the '''while loops'''. |
|- | |- | ||
− | | 04 | + | | 04:50 |
− | | | The while statement allows us to perform a loop when a | + | | | The '''while''' statement allows us to perform a '''loop''' when a Boolean expression is '''true'''. |
|- | |- | ||
− | | 04 | + | | 04:55 |
− | | | At the beginning of the loop, if the expression is true, | + | | | At the beginning of the '''loop''', if the expression is '''true''', |
|- | |- | ||
− | | 04 | + | | 04:58 |
− | | |the statements in the body of the while loop are executed. | + | | |the statements in the body of the '''while loop''' are executed. |
|- | |- | ||
− | | 05 | + | | 05:02 |
− | | | If the program is written well, the expression becomes false and the loop is ended. | + | | | If the program is written well, the expression becomes '''false''' and the '''loop''' is ended. |
|- | |- | ||
− | | 05 | + | | 05:08 |
− | || Now let us see an example for the while loop: | + | || Now let us see an example for the '''while loop''': |
|- | |- | ||
− | |05 | + | |05:15 |
− | | | The values of i, from 1 to 6 are displayed. | + | | | The values of 'i', from 1 to 6 are displayed. |
|- | |- | ||
− | |05 | + | |05:19 |
− | || Break and continue statements inside the while loop work exactly as they did in the for loop | + | || '''Break''' and '''continue''' statements inside the '''while loop''' work exactly as they did in the '''for loop''' as we demonstrate using '''break''': |
|- | |- | ||
− | |05 | + | |05:33 |
− | | | We can see that the moment i becomes equal to 3, the program exits the loop, thanks to the break statement. | + | | | We can see that the moment 'i' becomes equal to 3, the program exits the '''loop''', thanks to the '''break''' statement. |
|- | |- | ||
− | | 05 | + | | 05:39 |
− | || You can also try the example for continue statement in while loop. | + | || You can also try the example for '''continue''' statement in '''while loop'''. |
|- | |- | ||
− | | 05 | + | | 05:44 |
− | | | This brings us to the end of this spoken tutorial on iterative calculations using Scilab. | + | | | This brings us to the end of this spoken tutorial on '''iterative calculations''' using Scilab. |
|- | |- | ||
− | | 05 | + | | 05:50 |
|| Spoken Tutorials are part of the Talk to a Teacher project, supported by the National Mission on Education through ICT. | || Spoken Tutorials are part of the Talk to a Teacher project, supported by the National Mission on Education through ICT. | ||
|- | |- | ||
− | + | | 05:57 | |
− | | 05 | + | |
− | + | ||
| | More information on the same is available at the following link [http://spoken-tutorial.org/NMEICT-Intro]. | | | More information on the same is available at the following link [http://spoken-tutorial.org/NMEICT-Intro]. | ||
|- | |- | ||
− | + | | 06:00 | |
− | | 06 | + | | |Thanks for joining. Good bye. |
− | + | ||
− | | |Thanks for joining.Good bye. | + | |
|} | |} |
Latest revision as of 20:08, 25 February 2015
Time | Narration |
00:01 | Welcome to the spoken tutorial on iterative calculations using Scilab. |
00:07 | I am using Scilab version 5.2 in Mac operating system |
00:11 | but these calculations should work in other versions and also in Scilab that runs in Linux and Windows. |
00:17 | I will use the code available in the file 'iteration.sce'. |
00:22 | I have opened this file using Scilab editor which I plan to use only as an editor. |
00:29 | Let us create a vector using the colon operator. 'i' is equal to 1 colon 5, |
00:38 | creates a vector from 1 to 5, in increments of 1. |
00:42 | In this command, 'i' is equal to 1 colon 2 colon 5. |
00:51 | We see that the middle argument of 2 indicates the increment. |
00:56 | 1 is the first argument where the vector starts. 'i' cannot go beyond 5, |
01:01 | it can be equal to 5, however. |
01:04 | Note that if the ending argument changes to 6 the result remains the same. |
01:09 | It is not difficult to explain this behavior. |
01:13 | Can you think for a moment why this happens? |
01:15 | We will now demonstrate the use of the for statement to perform iterative calculations. |
01:22 | for i is equal to 1 colon 2 colon 7 disp i end of for loop. |
01:28 | I will cut this, paste in Scilab console, press Enter. |
01:34 | This code prints out 'i' as we go through the loop. |
01:37 | The display is due to the command disp - the passed argument is displayed. |
01:42 | Recall that the for loop is used for integer values. |
01:45 | In this case, four integer values, namely, 1, 3, 5 and 7 are displayed. |
01:50 | The number of times the iterations take place is known as priori in for loops. |
01:56 | In the rest of this tutorial, we will stick to the default increment of 1. |
02:01 | Let us begin with the loop that displays 'i' equal to 1 to 5. |
02:10 | We will modify this code by introducing the break statement. |
02:18 | Note that 'i' is displayed only up to 2. |
02:22 | The iteration is not carried out till the last value of i, namely 5. |
02:27 | When i is equal to 2, the if block is executed for the first time. |
02:30 | The break command, however, terminates the loop. |
02:34 | If we want to get out of a loop when some intermediate condition is satisfied, we can use the break statement. |
02:40 | Note that "i is equal to 2" statement uses the "equal to" sign twice. |
02:45 | This is the standard way to compare the equality in programming languages. |
02:50 | The result of this comparison statement is a Boolean: true or false. |
02:56 | We will introduce the continue statement here, paste, press Enter. |
03:06 | This results in 'i' getting displayed only for 4 and 5. |
03:10 | For 'i' less than or equal to 3, as given by the i less than or equal to 3 statement, nothing happens. |
03:18 | The continue statement makes the program skip the rest of the loop. |
03:22 | Unlike the break statement, however, it does not exit the loop. |
03:25 | The parameter 'i' is incremented and all the calculations of the loop are executed for the new i. |
03:32 | We take a small break and show how to get help for operators of the type 'less than or equal to' (<=). |
03:38 | Let us type 'less than or equal to with help'. |
03:46 | This opens the Scilab Help Browser. |
03:51 | We see that the help is available under the option less. |
03:56 | So now after closing this, we type help less. |
04:06 | We see the required help instructions here. I will close this. |
04:11 | The for statement in Scilab is more powerful than in programming languages. |
04:16 | For example, let us perform a loop over a vector: |
04:24 | This script displays all values of 'v'. |
04:28 | Until now we have been displaying only the variables. |
04:32 | We can indeed display the result of a calculation as well. |
04:35 | The following code displays the square of the numbers. |
04:44 | We have spent quite a bit of time explaining the for loop. |
04:48 | Let us now move on to the while loops. |
04:50 | The while statement allows us to perform a loop when a Boolean expression is true. |
04:55 | At the beginning of the loop, if the expression is true, |
04:58 | the statements in the body of the while loop are executed. |
05:02 | If the program is written well, the expression becomes false and the loop is ended. |
05:08 | Now let us see an example for the while loop: |
05:15 | The values of 'i', from 1 to 6 are displayed. |
05:19 | Break and continue statements inside the while loop work exactly as they did in the for loop as we demonstrate using break: |
05:33 | We can see that the moment 'i' becomes equal to 3, the program exits the loop, thanks to the break statement. |
05:39 | You can also try the example for continue statement in while loop. |
05:44 | This brings us to the end of this spoken tutorial on iterative calculations using Scilab. |
05:50 | Spoken Tutorials are part of the Talk to a Teacher project, supported by the National Mission on Education through ICT. |
05:57 | More information on the same is available at the following link [1]. |
06:00 | Thanks for joining. Good bye. |