Difference between revisions of "Scilab/C2/Getting-Started/English-timed"

|00.03

|'''Welcome to the spoken tutorial on Getting Started with Scilab.'''

| '''In this tutorial we are going to learn: '''

|00.10

| ''' The use Scilab as a calculator.'''

|00.13

| '''How to Store values in a variable.'''

|00.16

| '''How to Perform various mathematical operations using these variables.'''

|00.22

| '''How to Create a file to store commands executed during the session in the current working directory.'''

| ''' How to define complex numbers.'''

|00.32

| '''How to Perform exponential, logarithmic and trigonometric operations on numbers.'''

|'''The prerequisite for this tutorial are Scilab should be installed on your computer.'''

|00.45

| '''I am using Scilab 5.2.0 and Mac OS(X) for demonstration'''

|00.52

|'''Here is the Flow chart for the tutorial.'''

|'''Click on the Scilab shortcut icon on your Desktop and Start Scilab.'''

| '''This is the Scilab console window. Notice that the cursor is on the command prompt.'''

| '''I suggest that you practice this tutorial in Scilab simultaneously while pausing the video at regular intervals of time.'''

|01.17

|'''Scilab can be used as a calculator. Let us see some of the basic operations that it can do.'''

| '''Type 42 plus 4 multiplied by 4 minus 64 divided 4 and press enter.'''

| '''The output is 42, as expected.'''

|01.40

|'''Note that the answer 42 is stored in the default variable "a n s".'''

|'''We can also create named variables:''' '''Type, '''

| '''a equals 12,b=21 , and c=33 and press enter.'''

| '''This stores the values 12,21 and 33 in the variables a,b and c respectively.'''

| '''I will clear the scilab console using the clc command here'''

|02.14

|'''Now we will perform some mathematical operations using these variables. '''

|02.20

| '''For example,'''

| '''a+b+c gives the result 66 '''

|'''also'''

| '''a times into bracket (b+c) gives the result 648'''

|02.42

|'''We can also assign the answer to another variable say 'd' by typing d = bracket (a+b)

| '''d = 1089.'''

|03.02

|'''We can check the values in the variables by typing the names of the variables separated by commas on the command line as '''

| '''a,b,c,d and press enter'''

| '''I will clear the console here using the clc command'''

|03.22

|'''To take the power, use the “raised to” symbol which is located on the number key 6 of your keyboard.

| for example, 7 square can be found by 7 raised to 2 and press Enter.'''

|03.44

|'''For finding the square root of a number, say, 17, we use : sqrt(17).'''

|'''This is same as 17 raised to the power of zero point five. '''

|'''By convention, only the positive value comes as output.

| More generally, to find 34 to the power of (2 by 5), type:'''

|34 raised to bracket (2 divide by 5) and press Enter.

| '''Negative powers can also be used,

|04.34

| '''So far, we have seen how to do some simple calculations and how to create variables in Scilab. '''

|04.41

| '''Now let us start with the new command.

|04.44

| This will helps remember command which were previously issued along with the outputs.'''

| '''First type the command pwd and press Enter'''

| '''This is the current working directory (on my computer). '''

|04.59

|'''The current working directory can be changed by clicking the changed current directory icon located on the toolbar of the scilab console window as you see.

|'''Now issue the diary command by typing:'''

| '''diary bracket, open inverted commas, ('myrecord.txt') close inverted commas, close the bracket and press enter'''

|05.41

|'''This command will create a file with the name "myrecord.txt" in the current working directory. '''

| '''A transcript of the Scilab session from now onwards will be saved in this file. '''

| '''Its usefulness will be demonstrated at a later stage in this tutorial'''

|'''Please pause the tutorial now and attempt exercise number one given with the video. '''

|'''Now, let us see how Scilab handles complex numbers. '''

| '''The imaginary unit i is defined in Scilab as percent i:'''

|06.19

| For example '''(Five point two multiplied percent i gives 5.2i'''

|'''also bracket ( 10 plus 5 into percent i whole multiply by 2 times percent i gives the result -10. + 20.i'''

|'''Let us see some other predefined numerical constants available in Scilab. '''

| '''As with i, their names also start with the percent sign:'''

| '''For example, percent pi'''

| '''The value of pi is as expected.'''

|'''Now, we will demonstrate the use of pi using a few built-in trigonometric functions as follows. '''

|07.28

| '''For the functions sin of percent pi by 2 the result is 1''''

| '''Notice that the second answer is zero for all practical purposes. '''

| '''%eps is related to number known as "machine epsilon",'''

|08.04

| '''It is the minimum digit resolution that Scilab can give.'''

| '''On my computer it gives 2.220D-16 '''

| '''This shows the floating point precision used by Scilab . '''

| '''This number is a notation for 2.22 times 10^(-16). ''' Clear the console here.

|'''If one wants to write 0.000456, one can write it as 4.56d-4 or 4.56e-4'''

| '''While scilab variables and functions are case-sensitive, here we can use small d or capital D, or small e, or capital E. '''

|09.17

|'''The base of the natural logarithm is another important predefined numerical constant:'''

|09.23

| '''percent e gives the result as expected. '''

|09.31

|'''We can achieve the same result with the function "e x p"'''.

| '''For example: exp bracket (1)'' close the bracket and press Enter

|09.45

| '''You can see both the answers are same'''

|'''similarly,'''

| '''%e square gives the following answer'''

|'''which can also be achieved by typing exp of 2 . '''

|'''The command log means the natural logarithm of a number, that is, to the base e. '''

|10.24

| '''Use log 10 for taking the logarithm with respect to base 10. '''

| '''For example, log10(1e-23) and press enter this gives the expected answer -23.

| '''We get complex numbers when taking logarithm of negative. For complex numbers you can check this for yourself type : log(-1) or log(%i) on your scilab console'''

|'''Now recall that we invoked a recording of all the typed commands into the file myrecord.txt through the diary command, now, let's see how to close that file and view it. '''

|11.14

| '''For closing the file, type,'''

| '''diary of zero'''

| '''This command will close and save the file myrecord.txt. '''

| '''Also recall that this file was created in current working directory, which in my case is desktop. '''

|'''Let us open this file to do click on the a Open-a-file shortcut icon on your scilab console window toolbar.'''

|'''Note that all transactions, both commands and the corresponding answers given by Scilab, have been saved into this file.'''

|I will close this file,click yes.

| '''We know that, while a program is being developed, one experiments a lot with the code before arriving at suitable code. '''

|'''Diary command helps to keep track of all the transactions'''.

| If you recall that, we have closed the file my record.txt using the command diary of zero.

| '''If we need to save the session once again, we need to issue the diary command again. '''

| ''' If the file contains some useful information, then one should use the some other file name in the diary command.'''

|'''Pause the video here and solve the second exercise given with the video.'''

|'''You may have noticed that the solution for the problem was not exactly zero.

| 13.24

| ''For more information on how to deal with this, type “help clean”.'''

|13.28

|'''In general, if you need help about a particular command, then the 'help' or help with an argument command can be used.

| '''For example,type “help chdir” on the scilab console and press enter.

| ''' I will increase the size of the help browser.'''

| ''Help chdir gives detained information on how to change the current working directory'.

| ''Another option is to click on the help browser icon on the toolbar of the scilab console window as you see''.

| '''Let me close the help browser and coming back to the slides.'''

| '''The up - down arrow keys can been used to see the previously executed commands.'''

| '''While using the up - down arrows, you can stop at any command,and press the Enter to execute it.'''

| '''You can edit the commands, if necessary.

| '' In fact, if you are looking for a previous command you typed, which started with the letter 'e', then type e, and then use up arrow key.'''

| '''Use the tab key to auto-complete the commad. It gives us all the available options to choose. '''

|15.08

|'''In this tutorial we have learnt : '''

| '''Use of Scilab as a calculator .'''

| '''Store the result in the default variable ans. '''

| '''Assign values to the variable using the equality sign.'''

|15.21

| '''Check values in variables by typing the name of the variable separated by commas on the console.'''

|15.29

| '''Check the current working directory using pwd command.'''

| '''Use diary command to save all commands typed on the console into a file.'''

| '''Define complex numbers, natural exponents and π using %i, %e and %pi respectively. '''

| '''Use help command for detailed information about any command.'''

|'''This brings us to the end of this spoken tutorial on Getting Started with Scilab.'''

| There are many other functions in Scilab which will be covered in other spoken tutorials.'''

| * '''This spoken tutorial has been created by the Free and Open Source Software in Science and Engineering Education(FOSSEE). '''

| * '''More information on the FOSSEE project could be obtained from [http://fossee.in/ http://fossee.in] or [http://scilab.in/ http://scilab.in] website '''

|16.23

|  '''Supported by the National Mission on Eduction through ICT, MHRD, Government of India. '''

| More information on this please visit spoken hyphen tutorial dot o r g slash NMEICT hyphen intro''

| '''This is Anuradha Amrutkar from IIT Bombay signing off.'''