Unix Shell Learning

1. Create aliases
• Know your shell first;
• # echo $SHELL
• If output = '/bin/csh', type 
• # echo ls   'ls -al' >> ~/.cshrc
• Else if o/p = '/bin/bash', type 
• # echo 'ls = 'ls -al' >> ~/.bashrc
• And then type
• # source ~/.cshrc
  
2. 
   

Argument List in main() function

main(int argc, char** argv)

(The syntax char** argv declares argv to be a pointer to a pointer to a character, that is, a pointer to a character array (a character string)--in other words, an array of character strings. You could also write this as char* argv[]. Don't worry too much about the details of the syntax, however--the use of the array will be made clearer below.)

When you run a program, the array argv contains, in order, all the information on the command line when you entered the command (strings are delineated by whitespace), including the command itself. The integer argcgives the total number of strings, and is therefore equal to equal to the number of arguments plus one. For example, if you typed

 a.out -i 2 -g -x 3 4

the program would receive

 argc = 7
 argv[0] = "a.out"
 argv[1] = "-i"
 argv[2] = "2"
 argv[3] = "-g"
 argv[4] = "-x"
 argv[5] = "3"
 argv[6] = "4"

OpenSuse 11.x kNetworkManager issues

If you are facing issues with the OpenSuse's (11.x ; 3 >= x >= 0) default Connection Manager, install the "wicd" network configurator.

http://software.opensuse.org/ymp/X11:xfce:nilda/openSUSE_11.3/wicd.ymp?base=openSUSE%3A11.3&query=wicd

Enjoy!!

Latex tips and tricks - keep checking for newer ones

Some  tips,

• While creating a new book or article, if you intend to have a modified family of default font across all the pages in your doc, use
               " \renewcommand{\familydefault}{\sfdefault} "
  in the preamble. The above, for example, sets the font to sans serif.
  
  
• How to embed an image into a table? - Use the graphicx package and your problem is solved.
  

  \begin{table}[ht]

  \caption{A table arranging images}
  \centering
  \begin{tabular}{cc}
  \includegraphics[scale=1]{graphic1}&\includegraphics[scale=1]{graphic2}\\
  \newline
  \includegraphics[scale=1]{graphic3}&\includegraphics[scale=1]{graphic4}\\
  \end{tabular}
  \label{tab:gt}

  \end{table}%

  
  

Java and References

Point to note;

1. Java has pointers!!
   Java : Dog d = new Dog("Wicky"); is same as
   C++: Dog *d;
   
   
2. When you pass foo(d) in Java, you actually pass the pointer

New Hope to Moores Law

The new 3-D processor

I very much believed that Moores law is no longer true with the RND coming to a standstill to no longer being able to increase the number of transistors on a processor and (so) we have been going for multi cored architecture. However, Intel has found some new way to address this limitation. It might have thought "If not XY; haaa let me go for XYZ dimension!!" and it has come up with a production solution.

This is truly going to be a real Mile stone in hardware technology and even more promising to small scale devices like IPhones, handhelds and like for this new technology can save upto 50% of power.

Play this video for some experience of the new technology.

Sources

1. http://newsroom.intel.com/community/intel_newsroom/blog/2011/05/04/intel-reinvents-transistors-using-new-3-d-structure
2. http://www.hindu.com/seta/2011/05/19/stories/2011051950191300.htm

How to calculate 'differentiation' of a given function??

• Forward difference
  
  
  
  
  
  
  
• Centered difference
  
  
  
  
  
  

Now, using a computer one can easily compute the value of  up to a certain approximation. This is one such example where a continuous computation can be approximated using discrete formulation. The key here is the value of which should be chosen NOT too large (such that curvatures are totally avoided) nor too small (such that IEEE754 might fail to represent using the system hardware). Now, one can easily write off a C/Java program so as to calculate the differentiation of a function at a given value.

Refer "Press et al, Numerical Recipes, The Art of Scientific Computing, Cambridge Univ Press, III Ed, 2007" for more details.