Pop inspiration

http://www.mangafox.com/manga/shibao/v01/c001/1.html

Constants

The name tells'em all :

• e -- the base of natural logarithms
• pi -- the ratio of the circumference of a circle to its diameter
• Inf, inf -- infinity (∞)
• true, false -- boolean or logical truth values

octave:36> e

ans = 2.7183

octave:37> pi

ans = 3.1416

octave:38> inf

ans = Inf

octave:39> Inf

ans = Inf

octave:40> zero

octave:40>error: `zero' undefined near line 40 column 1

true

ans = 1

octave:41> false

ans = 0

octave:42>

Well, off the topic, we made a new discovery, observe the commands 40, 40 and 41.

"What!! It shud have been 40,41,42 right??"

Yes, indeed, but it means that the line numbers are allotted only to "successful commands", and not the ones resulting in error..... :)

Assignment and variables

The name of a variable can be any sequence of letters, digits and underscores or their combo,but the name must not begin with a digit.

There is no limitation of length to variable names, and are case is sIGnIfiCaNt.

i.e.

octave:30> apple=10;
octave:31> ApplE=90;
octave:32> apple + ApplE
ans = 100

In Octave a variable can take many different types of values; for example, it can take a numerical (real or complex) value, it can be a vector, or a matrix, or it can be a string (that is, a sequence of symbols).

A string is always placed between quote signs "..." so that Octave will know when the string starts and when it ends. The same variable can, at different times, hold each of these values. Lets see:

octave:34> first = "second"
first = second
octave:35> first
first = second

Elementary Mathematics

Back to LKG / UKG and standard 1st :)

Ok, lets pitch up with some basic calcs :
Oh yes, the octave:> thingy is the "prompt"....

octave:> 1 +1
ans = 2
octave:> 1+100;
octave:>

"Hey, hey hey .... hold your cats right there bro. Ok that 1+1 printed the ans as 2, but what about that 1 +100 calculation?? It didnt print... oh !! bugs right??"


Okay,

We may prevent octave from outputting results to the terminal by appending our commands with the semicolon “;”.

and if you want the results of your command to display ,do not append your command with a semicolon .

So going forward , we may try out some combinations like :

octave:21> 2 * 3

ans = 6

octave:22> 9 - 45

ans = -36

octave:23> 67 * 20

ans = 1340

octave:24> 23 ^ 15

ans = 2.6664e+20

octave:25>

Oh, those :21, :22s are the command numbers actually :):) ( i guess so :) )

Starting and Exiting Octave

Yep,

In order to launch Front end:
1. Either navigate thru Applications,
or
2. Type the following on terminal and hit 'enter' gently :)

qtoctave

Which will then launch the frontend , which looks like :



Now for exiting from Octave, just type:

> quit;

Installing Octave

Well,

On a Fedora machine powered with Internet,just like the one I have, log into terminal (... hmmm.. the command prompt for Linux...eh !! ), sudo using the command

> su

followed by your password,

> yum -y install qtoctave

.. ta da... !!

you will have octave as well as its GUI named QTOctave available for exploring.

Hmmm... I should have placed a post regarding yum, Synaptic Package manager, and building of .tar files... but then why is Internet for??.... ha ha !!

Octave

What is Octave?
-----------------

Octave is an open-source interactive software system for numerical computations and graphics, highly compatible with MATLAB, which is :-
- particularly designed for matrix computations,
- solving simultaneous equations,computing eigen vectors and eigen values
- and exploring deep into DSP, circuit analysis and so on....

( Yes, everything which scares the Mickey off almost every engineering student in initial years :) )

In addition, Octave can display data in a variety of different ways, and it also has its own extensible programming language . It canbe thought of as a very powerful, programmable, graphical calculator. Octave makes it easy to solve a wide range of numerical problems.

Octave was originally developed (hmmm.. in 1988 ) as a companion software to a undergraduate coursebook on chemical reactor design being written by James B. Rawlings of the University of Wisconsin-Madison and John G. Ekerdt of the University of Texas.

It is currently being developed under the leadership ofDr. J.W. Eaton and released under the GNU General Public Licence. Octave’s usefulnessis enhanced in that it is mostly syntax compatible with MATLAB which is commonly used in industry and academia.

"Ye ye !! big deal !!! never heard of anyone using it!! "

Well,

• NASA use it to develop spacecraft docking systems;
• Jaguar Racing use it to display and analyse data transmitted from their Formula 1 cars;
• Sheffield University use it to develop software to recognise cancerous cells;
• Pittsburgh supercomputing center used it to find vulnerability related to guessing social security numbers.

It makes it very easy to write mathematical programs quickly, and display data in a wide range ofdifferent ways.

** Write up sourced from Dr. P.J.G. Long's paper and Octave official site.

http://www.octave.org

Linux Directory Structure

A basic Linux directory structure is as follows, in which files are grouped according to usage....

/   Root
|---root  The home directory for the root user
|---home  Contains the user's home directories
|    |----ftp  Users include many services as listed here
|    |----httpd
|    |----samba
|    |----user1
|    |----user2
|---bin   Commands needed during bootup that might be needed by
|                       normal users.
|---sbin  Like bin but commands are not intended for normal users.
|                       Commands run by LINUX.
|---proc  This filesystem is not on a disk.Exists in the kernels
|    |                  imagination (virtual).  This directory
|    |   Holds information about kernel parameters and system
|    |                  configuration.
|    |----1  A directory with info about process number 1.Each
|                       process has a directory below proc. 
|---usr   Contains all commands, libraries, man pages, games and
|    |                  static files for normal operation.
|    |----bin  Almost all user commands.  some commands are in /bin or /usr/local/bin.
|    |----sbin  System admin commands not needed on the root filesystem.  e.g., most server
|    |   programs.
|    |----include Header files for the C programming language.  Should be below /user/lib for
|    |   consistency.
|    |----lib  Unchanging data files for programs and subsystems
|    |----local  The place for locally installed software and other files.
|    |----man  Manual pages
|    |----info  Info documents
|    |----doc  Documentation for various packages
|    |----tmp
|    |----X11R6  The X windows system files.  There is a directory similar to usr below this
|    |   directory.
|    |----X386  Like X11R6 but for X11 release 5
|---boot  Files used by the bootstrap loader, LILO.  Kernel images are often kept here.
|---lib   Shared libraries needed by the programs on the root filesystem
|    |----modules  Loadable kernel modules, especially those needed to boot the system after
|    disasters.
|---dev   Device files for devices such as disk drives, serial ports, etc.
|---etc   Configuration files specific to the machine.
|    |----skel  When a home directory is created it is initialized with files from this directory
|    |----sysconfig  Files that configure the linux system for networking, keyboard, time, and more.
|---var   Contains files that change for mail, news, printers log files, man pages, temp files
|    |----file
|    |----lib  Files that change while the system is running normally
|    |----local  Variable data for programs installed in /usr/local.
|    |----lock  Lock files.  Used by a program to indicate it is using a particular device or file
|    |----log  Log files from programs such as login and syslog which logs all logins,
|    |   logouts, and other system messages.
|    |----run  Files that contain information about the system that is valid until the system is
|    |   next booted
|    |----spool  Directories for mail, printer spools, news and other spooled work.
|    |----tmp  Temporary files that are large or need to exist for longer than they should in
|    |   /tmp.
|    |----catman A cache for man pages that are formatted on demand
|---mnt   Mount points for temporary mounts by the system administrator.
|---tmp   Temporary files.  Programs running after bootup should use /var/tmp.




Source : www.comptechdoc.org

First Flood...

Hi all,
Its Dipan Chandra here. It is my first blog and I am a FOSS enthusiast wetting my hands as of now in "Octave" ( FOSS equivalent of MALAB ), PHP and Open source Content Management.

Lets see how long I sail..


chow..