Difference between revisions of "Scilab/C2/Scripts-and-Functions/English"

These are called SCRIPT files.

whereas

Files having the .sce extension can contain both Scilab function definitions as well as executable statements (including function calls).

Check the present working directory by typing pwd on the command prompt

-->pwd

ans =

C:\Documents and Settings\cdeep_lap12

a=1; b=2; c=a+b;

d=a+b+c;

disp(d)

disp("Goodbye World")

This will load the file in scilab console.

-->disp("Hello World")

Hello World

--> a=1; b=2; c=a+b;

--> d=a+b+c;

--> disp(d)

6.

--> disp("Goodbye World")

Goodbye World

-->exec("helloworld.sce")

-->disp("Hello World")

Hello World

-->a=5; b=2; c=a+b;

-->d=a+b+c;

-->disp(d)

14.

-->disp("Goodbye World")

Goodbye World

A function definition starts with the keyword function and ends with the keyword endfunction.

The function is defined as you see,

degrees = radians*(180/%pi);

endfunction

I will now load this function in Scilab using the Execute menu option.

-->exec functions.sci

-->function [degrees] = radians2degrees(radians)

--> degrees = radians*(180/%pi);

-->endfunction

-->radians2degrees(%pi/2)

ans =

90.

-->radians2degrees(%pi/4)

ans =

45.

This function will takes polar coordinates as input argument and returns rectangular coordinates as output arguments.

x = r*cos(theta*%pi/180)

y = r*sin(theta*%pi/180)

endfunction

-->exec polar2rect.sci

---> r = 2;

---> theta = 45;

-->[x1, y1] = polar2rect(2,45)

y1 =

1.4142136

x1 =

1.4142136

These variables won't get mixed up unless we use the global option.

Also check this for disp("...") statements.

Functions are segments of code that have well defined input and output as well as local variables.

The simplest way to define a function on the interpreter itself is by using the command `deff'.

This can be done with the help of the function deff().

It takes two string parameters.

The first string defines the function declaration and the second string defines the statements of the function.

There is no need to load the function defined by using deff command explicitly through execute menu option since this is not being saved in a script file.

deff("[radians] = degrees2radians(degrees)","radians = degrees*(%pi/180)")

-->degrees2radians(90)

ans =

1.5707963

-->degrees2radians(45)

ans =

0.7853982

This is "recursive" calling of a function.

This is required, for example, when writing a function to calculate the factorial of an integer.

As mentioned earlier SCILAB uses two types of file formats, namely the SCE file format and the SCI file format.

The files with the .sce file extension are the script files, which contain the SCILAB commands that you enter during an interactive kind of SCILAB session.

They can also have comment lines used for documenting the script and they can also use the command EXEC to execute the script.

The files with the .sci file extension are the function files that start with the function statement.

A single .sci file can have multiple function definitions which themselves contain any number of SCILAB statements that perform operations on the function arguments, or on the output variables after they have been evaluated.

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

Keep watching the Scilab links.

More information on the FOSSEE project could be obtained from http://fossee.in or http://scilab.in

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

For more information, visit:

http://spoken-tutorial.org/NMEICT-Intro

This is Anuradha Amrutkar from IIT Bombay signing off.

Good bye