Desert Rose

OpenCV installation

2012-01-30T11:37:00.003-05:00

Here goes the steps: Installation steps

Finally compiling program with opencv:
Setup the PKG_CONFIG_PATH variable
export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig
export LD_LIBRARY_PATH=/usr

You can check that the PKG_CONFIG_PATH is correct by doing either:
pkg-config --cflags opencv
pkg-config --libs opencv

Compile and link the sample code on OS/X:
You can compile and run the sample code from the directory it's installed in "testcode.cpp":
g++ -bind_at_load `pkg-config --cflags opencv`testcode.cpp -o testcode `pkg-config --libs opencv`
./testcode

The image will show up in a window.
Tutorials on OpenCV can be found here.

Reference

Alternately, it can be installed using macport. Here are the instructions. Reference.

Java from command prompt in windows :@

2012-01-26T13:50:00.002-05:00

THIS FREAKING PATH VARIABLE UPDATE IS SO ANNOYING. KILL YOU FOOL.

Additional note is that, if java -version, javac -version do not give the same version then you have problem. You should also change/add path to the ../jre/bin path into the PATH variable as well.

Reference

Matlab updating the path directory

2012-01-24T14:13:00.000-05:00

Append new directory:
p = path;
path(p, '/Users/hello/Desktop/directory/);

Remove a directory from the path:

rmpath('/Users/hello/Desktop/directory/);

Reference

Simple logic but doesn't easily stick to our memory

2012-01-24T02:27:00.001-05:00

Science articles

2012-01-23T22:53:00.002-05:00

My Birthday

2012-01-23T22:08:00.001-05:00

Rule of success

2012-01-23T15:46:00.001-05:00

WTF

2012-01-21T15:48:00.000-05:00

Landlord got killed in his own house in Mirpur, Dhaka: 1/21/2012

I need to talk to you

2012-01-21T02:26:00.001-05:00

Monkey business

2012-01-20T00:46:00.002-05:00

Reference

Laughter show: Girl with the dragon tattoo

2012-01-20T00:37:00.002-05:00

YORICK VAN WAGENINGEN
Rooney, you've been declared mentally incompetent by the state because your hair is weird and your earrings look kinda like the aforementioned hair. As a result I've been assigned as your guardian to manage all of your finances, which I'm more than happy to do after putting my greasy wiener in your mouth.

ROONEY MARA
I'll do this, but only because being emotionally scarred is the easiest way to add a shred of complexity to an invincible ass-kicking ninja bisexual superhacker.

YORICK VAN WAGENINGEN
Holy shit, that worked? In that case, I'm going to tie you down and violently sodomize you as well.

ROONEY MARA
Hey, rape is one thing, but anal rape is crossing the line! Now I will seek revenge by sodomizing you with a steel dildo and tattooing you with the list of movie roles you will never be offered because you took this one!

Reference: Girl with the dragon tattoo in 5 minutes

Redshift vs Blueshift

2012-01-19T17:07:00.001-05:00

Experimental evaluation on intercessory prayer on critical patient

2012-01-19T16:13:00.002-05:00

Evaluating Extraordinary Claims: "Mind over matter? or Mind over Mind"

Palindrome

2012-01-19T15:22:00.000-05:00

A man, a plan, a caret, a ban, a myriad, a sum, a lac, a liar, a hoop, a pint, a catalpa, a gas, an oil, a bird, a yell, a vat, a caw, a pax, a wag, a tax, a nay, a ram, a cap, a yam, a gay, a tsar, a wall, a car, a luger, a ward, a bin, a woman, a vassal, a wolf, a tuna, a nit, a pall, a fret, a watt, a bay, a daub, a tan, a cab, a datum, a gall, a hat, a fag, a zap, a say, a jaw, a lay, a wet, a gallop, a tug, a trot, a trap, a tram, a torr, a caper, a top, a tonk, a toll, a ball, a fair, a sax, a minim, a tenor, a bass, a passer, a capital, a rut, an amen, a ted, a cabal, a tang, a sun, an ass, a maw, a sag, a jam, a dam, a sub, a salt, an axon, a sail, an ad, a wadi, a radian, a room, a rood, a rip, a tad, a pariah, a revel, a reel, a reed, a pool, a plug, a pin, a peek, a parabola, a dog, a pat, a cud, a nu, a fan, a pal, a rum, a nod, an eta, a lag, an eel, a batik, a mug, a mot, a nap, a maxim, a mood, a leek, a grub, a gob, a gel, a drab, a citadel, a total, a cedar, a tap, a gag, a rat, a manor, a bar, a gal, a cola, a pap, a yaw, a tab, a raj, a gab, a nag, a pagan, a bag, a jar, a bat, a way, a papa, a local, a gar, a baron, a mat, a rag, a gap, a tar, a decal, a tot, a led, a tic, a bard, a leg, a bog, a burg, a keel, a doom, a mix, a map, an atom, a gum, a kit, a baleen, a gala, a ten, a don, a mural, a pan, a faun, a ducat, a pagoda, a lob, a rap, a keep, a nip, a gulp, a loop, a deer, a leer, a lever, a hair, a pad, a tapir, a door, a moor, an aid, a raid, a wad, an alias, an ox, an atlas, a bus, a madam, a jag, a saw, a mass, an anus, a gnat, a lab, a cadet, an em, a natural, a tip, a caress, a pass, a baronet, a minimax, a sari, a fall, a ballot, a knot, a pot, a rep, a carrot, a mart, a part, a tort, a gut, a poll, a gateway, a law, a jay, a sap, a zag, a fat, a hall, a gamut, a dab, a can, a tabu, a day, a batt, a waterfall, a patina, a nut, a flow, a lass, a van, a mow, a nib, a draw, a regular, a call, a war, a stay, a gam, a yap, a cam, a ray, an ax, a tag, a wax, a paw, a cat, a valley, a drib, a lion, a saga, a plat, a catnip, a pooh, a rail, a calamus, a dairyman, a bater, a canal--Panama. --Dan Hoey, 'discovered' in 1984.

Panama Palindrome

More Palindrome

Abbu's favorite singer, Mehdy Hasan, is in crtical situation

2012-01-18T21:53:00.002-05:00

Reference: Mehdy Hasan

Fitting gaussian mixture model to the data

2012-01-18T15:58:00.000-05:00

Here I have generated a mixture distribution using two gaussians: 1) Mean=3, Variance=1, 2) Mean=10, Variance=2, respectively. Then fit the mixture distribution using Matlab's gmdistribution.fit(), which estimates the mixture model parameters using Expectation Maximization algorithm.

MU1 = [3];
SIGMA1 = [1];
MU2 = [10];
SIGMA2 = [2];
X = [mvnrnd(MU1,SIGMA1,100);
mvnrnd(MU2,SIGMA2,100)];
% scatter(X(:,1),X(:,2),10,'.')
figurehist(X)title('histogram')
pause;
close;
options = statset('Display','final');
obj = gmdistribution.fit(X,2,'Options',options);
ComponentMeans = obj.mu
ComponentCovariances = obj.Sigma

Reference from Mathworks Matlab

Plotting multiple histograms in different color: Matlab

2012-01-18T02:20:00.002-05:00

histograms-of-two-set-of-data-with-different-color-in-matlab

Clean sweep

2012-01-14T01:35:00.002-05:00

Image file formats

2012-01-13T16:32:00.000-05:00

BMP:
JPG:
GIF:
PNG:
PGM: Portable Gray Map
TIFF:

Premonition

2012-01-13T04:11:00.001-05:00

Success

2012-01-12T02:04:00.004-05:00

Credit: From Jahid (36th Batch, RCC)'s wall in facebook.

Cumulonimbus

2012-01-11T16:36:00.001-05:00

Rejection for the "Automatic Courtship Suppression paper" from "Learning and Memory" Journal :(

2012-01-10T13:45:00.001-05:00

We submitted our work on "Drosophila" in a journal, Learning and Memory few days ago. It got rejected by saying that - there is not enough conceptual advance for the brief communication in the journal.

It feels bad. How long I have to wait, I do not know. Just feels bad. We will give it more tries on other journals on the pipeline - Fly, Plos-One - with enhancement of words that better communicates our idea.

Allah please make it successful this time.

Thought at dealth-bed

2012-01-10T01:36:00.001-05:00

What people thinks at their death-bed.

Samson Chowdhury: [1926-2011]

2012-01-05T17:47:00.002-05:00

A successful businessman from Bangladesh

Potrait from Bangladesh

2012-01-04T01:38:00.003-05:00

Reference

Thanking the adversity: Albert Einstein

2011-12-30T16:51:00.000-05:00

The expression of hands

2011-12-30T12:41:00.002-05:00

Reference: www.metmuseum.org

Murray and Dick

2011-12-30T03:26:00.001-05:00

Neither Feynman nor Gell-Mann got what he most wanted. Feynman never stopped lamenting that he had missed the thrill of being the first to understand a new truth. Gell-Mann has never become a household name. And the friction between them prevented the kind of alliance that might have led to even greater discoveries -- great enough, perhaps, to satisfy both these impossible men.

Reference

Double sided disabled during printing in OSX

2011-12-20T11:33:00.001-05:00

Whenever I add a new printer the double-sided option is generally disabled. It is not about installing the printer driver in OSX. Just let the system know that it should allow duplex printing. Change the settings from system preference. Here is the helpful instruction to enable the setting.
Reference: enabling-two-sided-duplex-printing-on-mac

Matlab functions that that I used

2011-12-19T13:36:00.004-05:00

unique
intersect
load: load the mat file into the workspace.
ind2sub: Subscripts from linear index
matlab-remove-all-unwatned-elements-in
NaN: The IEEE floating point format used by most modern computers supports values that are "not a number". These values are called NaNs. "Not a number" values result from certain operations which have no meaningful numeric result, such as zero divided by zero or infinity divided by infinity.
cond: Condition number with respect to inversion

Alamgir bhai's column on bdnews

2011-12-16T06:38:00.002-05:00

প্রিয়-তরুণ-প্রজন্ম

PCEmulator in pure javascript

2011-12-15T07:01:00.002-05:00

http://bellard.org/jslinux/

Common birthday probability

2011-12-08T18:17:00.001-05:00

বেঙ্গলেনসিস/গণিতের-সৌন্দর্য্য-পর্ব-১

No freakng out. If you are stressed, enjoy it as if they are desserts

2011-12-08T17:37:00.001-05:00

RIP Dev Anand

2011-12-04T06:35:00.001-05:00

Bollywood-mourns-Dev-Anand-s-death: Dead after having a cardiac arrest

Struggle with technical issues

2011-12-04T05:54:00.001-05:00

K-means problem while working on segmentation: Reference

Search tricks in Google

2011-12-02T23:57:00.001-05:00

Often I need to search for a specific file. Rather than grappling in the dark by doing a brute force search, a file can be easily found by some additional tricks. Thanks Reference, for compiling the tricks.

For specific file: Site:mediafire.com Mp3|wma|aac|wav “billy jean”. Just by changing the type of file a different type of file can be found. For video file, asf|rm|avi|mp4|wmv|flv. For pdf change to pdf. For zipped file, zip|rar|7zip|tar.
To download a song use index search: intitle:”index.of”(mp3|mp4|avi) “billy jean”.
For e-book: Perfume filetype:pdf
Reference

(Static vs Dynamic) binding in Java

2011-12-02T09:03:00.001-05:00

dynamic-binding-vs-static-binding
Polymorphism via inheritance or interfaces are done by dynamic binding. They are bound during the run time.

late-binding-vs-static-binding
static methods, private methods, member variable initializations are done by static binding. They are done at compile time.
Compiler decides the member variable value depending on the type of reference that has been used when resolving member variable value with the same name from super and sub class.

Polymorphism via Inheritance and Interface

2011-12-02T03:29:00.001-05:00

Polymorphism: So it means entity that can have many forms. More specifically, a reference variable that can refer to different types of objects at different points of time. The specific method called through a polymorphic reference can change from one invocation to any subsequent invocations.
Java allows two kinds of polymorphism reference:

Polymorphism through inheritance:
For example think of a class hierarchy Object -> Animal -> Mammal -> Tiger
Animal objAnimal;
Mammal objMammal;
Tiger tigerObj = new Tiger("Bengal Tiger");
objAnimal = tigerObj; // Valid. objAnimal.move() will invoke the move method of Tiger class
objMammal = tigerObj // Valid. objMammal.move() will invoke the move method of Tiger class
objAnimal = new Tiger("Siberian Tiger"); // Valid. objAnimal.move() invoke the move() of Tiger class
Object obj = new Tiger("Thai Tiger"); // Valid. obj.move() will invoke the move method of Tiger class

At any point of time objAnimal can be used polymorphically, because it can refer to Animal object, Mammal object, or Tiger object. Particular version of move method that will be used depends on what kind of reference the objAnimal holds at a particular moment. Usually the children classes over-rides the method definitions. So each of the children in the Animal hierarchy has an different definition of move(). Depending on the reference class it is currently pointing to, a particular implementation of the move will be invoked.

Even if Mammal's move method is abstract it can invoke any of its children's move() (for example Tiger, Lion, Dolphin can have different implementation of move methods. Mammal reference can be used to instantiate any of these three objects and can be used to invoke move method at different points of time.)

Tiger tigerObj2 = objAnimal. //INVALID

Tiger tigerObj2 = (Tiger)objAnimal. //Valid.
But tigerObj may not have all the properties now because it is down-casted from its ancestor. It is less useful and tend to create problems.

Polymorphism through interface:
Interface can also have hierarchy. Child interface inherits all the methods/constants of its parents. No visibility issue since all methods and constant members are public.
An interface can be used to refer to any object of any class that implements it.

public interface Singer{
public void sing();
public void scream();
}

Singer singer = new ClassicalMusician(); // Valid
ClassicalMusician class implements the Singer interface. So singer reference can be used to refer to an object of ClassicalMusician.
singer.sing() //Valid
singer = new Cuckoo(); //Valid assuming Cuckoo class implements Singer interface.
singer.scream(); //Valid

Polymorphism via interface is different from polymorphism via inheritance in a sense that here the type of the object that the reference points to at the moment of invocation determines what code will be executed.

Unlike polymorphism via inheritance, we are allowed to invoke only those methods that are defined in the interface (in example more specifically the sing() and scream() methods only). If singer currently refers to an object of Cuckoo class, and singer invokes a singer.buildNest(), method from the Cuckoo, it will produce a compiler error.

However, if we have the knowledge in a particular situation that such invocation is valid, we can cast the object into the appropriate reference so that the compiler will accept it:
(Cuckoo)singer).buildNest(); //Valid. singer is converted to an object of Cuckoo then the buildNest() is invoked.

An interface name can be used as the type of a method parameter. In such situation, any object of any class that implements the interface can be passed into the method.
public void operaSinging(Singer obj) {
obj.sing();
}

Then we can pass instance of ClassicalSinger or an instance of Cuckoo to the operaSinging() method as a parameter.

Compiling source files: C/C++ vs Java

2011-12-01T19:56:00.001-05:00

Each time I switch between C/C++ and Java, I tend to forget the commands to compile the source files. I should make a post that makes sure I reminds (at least I don't forget) the difference between the two.

C/C++:
If I am trying to compile a file called main.cpp and it uses other file such as helperA.c and helperB.c; I would be using the command:
>>g++ -o main.o helperA.c helperB.c main.cpp

This will create an executable called main.o. I can run this executable using:
>>./main.o

Additional note is that C/C++ uses command line arguments in pointer to character array. An integer argc counts the number of arguments. For example,
int main(int argc, char* argv[]) {...
If I run the program using three arguments then argc will be 4 (3 arguments in addition to the name of the program in argv[0]). The first argv[0] will hold the name of the executable. The three arguments that I passed will be stored in argv[1], argv[2], and argv[3] respectively.

Java:
If I am trying to compile a file called Main.java and it uses other file such as HelperA.java and HelperB.java; I would be using the command:
>>javac -d bin -sourcepath src src/Main.java

Here I am assuming that I have the source files inside the directory src. To indicate that I used -sourcepath option. The compiled Main.class, HelperA.class, and Helper.B files will be created inside the folder bin. And I indicated that using the -d option.

Given the above compiled files, I will get inside the bin folder using the cd command. I can run this executable using:
>>java Main

As opposed to the C/C++ command line argument, Java uses only an array of String type. For example,
public static void main(String[] argv) {...
If I run the program using three arguments, then I can access those arguments inside the main by
argv[0], argv[1], and argv[2] respectively. Index in "String[] argv" starts from 0 as opposed to C/C++, which starts at 1 (index 0 there stores the executable name).

Abbu and a beautiful song by Hemanta

2011-11-28T21:48:00.001-05:00

This was Abbu's favorite song. He used to sing this. He had a nice and delicate voice. This post is is dedicated to his reminiscence.

Is it a coincidence?

2011-11-25T23:02:00.001-05:00

Few years ago, Mr Prasanna Kumar Paul (who was House Master of Tariq house while we were in RCC) did this being a principal there in CCR.
Mr Delowar incidence

Ponting still fighting

2011-11-24T15:08:00.001-05:00

an innings of 65 saved him

Reference

Latex quickies

2011-11-23T02:15:00.001-05:00

Union of sets: \begin{math}V = {\bigcup_{i}}^{k} S_{i}\end{math}

Mobile application development: Bangladeshi perspective

2011-11-21T02:00:00.001-05:00

মোবাইল-অ্যাপ্লিকেশন-ডেভে

Junit test in eclipse

2011-11-17T22:36:00.001-05:00

You can run a bunch of tests to verify the correctness of the implemented methods in a java class using Junit test. In order to do that, you have to write some junit test code in your program. Here goes the steps:

step 1: Download the junit jar file (e.g., you can download this one.)
step 2: Add the junit in your project path. (e.g., I already shown in another post how to that.)
step 3: Follow the example here to get an idea.
step 4: To gain more experience, try this exercise (from the class that I am TAing).

Adding jar files in eclipse

2011-11-17T22:23:00.001-05:00

Working with external libraries is a bit hassle when developing project using IDE. This was so annoying which eventually led me to quit the use of IDE. May be I was naive back then to cope up with the additional hassle. Anyway, here goes the stepwise instruction to add external jar files into your project in eclipse.

Daylight saving: the time chaning moment

2011-11-17T04:50:00.001-05:00

What is PhD? by Prof Mathew, UCSB

2011-11-17T03:11:00.001-05:00

http://www.cs.ucsb.edu/~mturk/PhD-notes.html

Reminiscence of 80s

2011-11-16T17:08:00.001-05:00

Reminiscence of old days of 80s: from adnan.quaium.com

Inspiration and copying

2011-11-14T16:02:00.001-05:00

How can you distinguish between taking inspiration and copying someone's work without giving him the credit. Here is a list of songs that were illegitimately taken from others.
www.itwofs.com

Reference: I found it from a Bangladeshi blog post. I here by giving him the credit of compiling or finding the source before me.

Road accient on Mymensing: Monowar from BUET ME'95

2011-11-10T18:47:00.001-05:00

Monowar Bhai (Sheetal's collegue at Vonair) falls victim to car accident

Good articles

2011-11-10T14:27:00.001-05:00

Planet of the Professors: www.cronicle.com
Writing down one's thought improves his performance: www.cricinfo.com
We did overcome: cricinfo
Winning is everything?
On earning not asking for respect: Michael Clarke's big score on 2nd test vs India, SCG, 2012.

It's time for Joe Frazier:1944-2011

2011-11-09T23:22:00.001-05:00

www.joefrazier.com
Report from Prothom-alo: Joe Frazier

Common mistakes

2011-11-09T14:42:00.002-05:00

1. Let me know if you have any comments and suggestions.
- plural is recommended, because it is stressing for more than one. Use of "comment" is not incorrect.
2. The only time you should spell “let’s” with an apostrophe is when it means “let us”: “Let’s go to the mall.” If the word you want means “allows” or “permits,” no apostrophe should be used: “My mom lets me use her car if I fill the tank.” Reference

Watershed transformation for segmentation

2011-11-08T22:33:00.002-05:00

http://cmm.ensmp.fr/~beucher/wtshed.html#watshed
http://www.mathworks.com/company/newsletters/news_notes/win02/watershed.html

Mex: Matlab Executables

2011-11-07T20:59:00.002-05:00

mex
To compile a mex file written in C programming language, e.g.,
mex test_mex.c other_C_file_the_mex_file_using.c -O % -v

Matlab image display

2011-11-07T20:59:00.000-05:00

image function can be used to display image.

When you read image data into the MATLAB workspace using imread, the data is usually stored as an array of 8-bit integers. However, imread also supports reading 16-bit-per-pixel data from TIFF and PNG files. These are more efficient storage methods than the double-precision (64-bit) floating-point numbers that MATLAB typically uses. However, it is necessary to interpret 8-bit and 16-bit image data differently from 64-bit data. This table summarizes these differences.

bhupen Hazarika: 1926-2011

2011-11-02T04:05:00.000-04:00

Bhupen Hazarika is in ICU
Bhupen Hazarika is no more

Lytro

2011-10-31T03:26:00.002-04:00

www.lytro.com
Light field camera.

What makes a good allrounder

2011-10-31T03:07:00.002-04:00

What makes a good allrounder

KirK Edwards

2011-10-30T19:23:00.001-04:00

‘লোকে যত বলে “আমি পারব না”, আমি ততই বলি “আমি পারব”। মানুষকে ভুল প্রমাণ করাতেই আমার আনন্দ।’ টেস্ট ক্রিকেটে পাঁচ ইনিংসে দ্বিতীয় সেঞ্চুরি—কার্ক এডওয়ার্ডস সেই পথেই আছেন।

Sparks: Chetan Bhagat

2011-10-30T13:34:00.002-04:00

অনুবাদ-sparks-chetan-bhagat

Siri

2011-10-29T15:59:00.003-04:00

why-siri-is-a-google-killer

Dark matter

2011-10-27T01:15:00.001-04:00

Dark matter

Guy Kawasaki: what-i-learned-from-steve-job

2011-10-27T01:03:00.002-04:00

what-i-learned-from-steve-jobs

Albert Einstein

2011-10-26T22:44:00.003-04:00

"We are in the position of a little child entering a huge library filled with books in many languages. The child knows someone must have written those books. It does not know how. It does not understand the languages in which they are written. The child dimly suspects a mysterious order in the arrangement of the books but doesn't know what it is. That, it seems to me, is the attitude of even the most intelligent human being toward God. We see the universe marvelously arranged and obeying certain laws but only dimly understand these laws." - Albert Einstein
Reference from Time

Bill Gates

2011-10-26T03:11:00.001-04:00

Kind of true

2011-10-25T23:20:00.001-04:00

Life

2011-10-25T20:35:00.001-04:00

Simple but valuable advice

2011-10-25T20:31:00.001-04:00

I. L. Bula

2011-10-25T20:24:00.002-04:00

Test player from Fiji with longest name: I._L._Bula

A watch

2011-10-22T15:16:00.001-04:00

I would love to have this Franck Muller watch. Only problem is that I can't afford it :(.

Conquistador-gpg(9900-sc-gp)

Cheap alternative from Joshua-Sons

Scary survival inside ship container

2011-10-21T19:59:00.000-04:00

A bengali survived after getting stuck inside a ship container for 3 days

Rokibul Hasan junior

2011-10-21T02:05:00.002-04:00

Rokibul Hasan: rise into the national team

Genius

2011-10-20T17:20:00.000-04:00

Genius is a talent for producing something for which no determinate rule can be given, not a predisposition consisting of a skill for something that can be learned by following some rule or other.—Immanuel Kant

Gaddafi is dead: Libyan revolution February'2011-October'2011

2011-10-20T14:33:00.000-04:00

How he died.
His female bodyguards.
His last wishes.

Watson's discovery moment

2011-10-20T05:33:00.001-04:00

"Fatefully, such amity did not prevail at a laboratory over at King's College, London, where a woman named Rosalind Franklin was creating the world's best X-ray diffraction pictures of DNA. Maurice Wilkins, a colleague who was also working on DNA, disliked the precociously feminist Franklin, and the feeling was mutual. By Watson's account, this estrangement led Wilkins to show Watson one of Franklin's best pictures yet, which hadn't been published. "The instant I saw the picture my mouth fell open," Watson recalled. The sneak preview "gave several of the vital helical parameters."
Full story

Cell animation

2011-10-20T04:49:00.001-04:00

Not to be afraid of speaking your mind

2011-10-17T16:00:00.002-04:00

Motivation

2011-10-16T00:18:00.001-04:00

Interface for comparing objects

2011-10-13T17:21:00.005-04:00

For example lets create an Interface Relatable that allows us to implement the isLargerThan() method to the class that implements this interface.

public interface Relatable {

// this (object calling isLargerThan) and
// other must be instances of the same class
// returns 1, 0, -1 if this is greater
// than, equal to, or less than other
public int isLargerThan(Relatable other);
}

If you want to be able to compare the size of similar objects, no matter what they are, the class that instantiates them should implement Relatable.

Any class can implement Relatable if there is some way to compare the relative "size" of objects instantiated from the class. For strings, it could be number of characters; for books, it could be number of pages; for students, it could be weight; and so forth. For planar geometric objects, area would be a good choice (see the RectanglePlus class that follows), while volume would work for three-dimensional geometric objects. All such classes can implement the isLargerThan() method.

If you know that a class implements Relatable, then you know that you can compare the size of the objects instantiated from that class.

MyRectangle Class implements Relatable interface. It must implement isLargerThan() method. Since MyRectangle class implements Relatable Interface, two objects of MyRectangle class can be compared.

// a method required to implement the Relatable interface
public int isLargerThan(Relatable other) {
RectanglePlus otherRect = (RectanglePlus)other;
if (this.getArea() < otherRect.getArea())
return -1;
else if (this.getArea() > otherRect.getArea())
return 1;
else
return 0;
}

Note:

The isLargerThan method, as defined in the Relatable interface, takes an object of type Relatable. The line of code, shown in bold in the previous example, casts other to a MyRectangle instance. Type casting tells the compiler what the object really is. Invoking getArea directly on the other instance (other.getArea()) would fail to compile because the compiler does not understand that other is actually an instance of MyRectangle.
Related reference that shows the similar Interface "Relatable"

When they implement Relatable, they can be of both their own class (or superclass) type and a Relatable type. This gives them some of the advantages of multiple inheritance, where they can have behavior from both a superclass and an interface.
Interface as type

Extending interface
Now users of your code can choose to continue to use the old interface or to upgrade to the new interface.

Dennis Ritchie departs: 1941-2011

2011-10-13T00:32:00.003-04:00

Bell Laboratories link
Wikipedia link
My first computer programming language is C. He was one of the inventors of C. This guy had profound impact in development of Computer Science.

Saving a session in Unix terminal

2011-10-12T13:50:00.002-04:00

Type:
script output.txt

Reference

In Lisp we can use (dribble "output.out")

Jagjit Singh: Gazal Singer

2011-10-11T19:45:00.001-04:00

Jagjit Singh dies on 10th October 2011

Bridhdhasrom

2011-10-08T18:05:00.001-04:00

bridhdhasrom

Physics Nobel prize in 2011

2011-10-08T11:59:00.003-04:00

Physics nobel winner 2011
Adam Riess from Johns Hopkins University shared the nobel prize in physics in this year 2011 along with two other men. He shared his reaction after winning the nobel prize in the above article.

The importance of stupidity in scientific research

2011-10-06T21:56:00.000-04:00

The article.
Nice reading.

Steve Jobs:1955-2011

2011-10-05T23:36:00.004-04:00

Various articles written on Jobs:
Prothom-alo article
স্টিভ-জবস-এর-জীবন-থেকে-নেয

Stroke

2011-10-05T23:29:00.002-04:00

S * Ask the individual to SMILE ..
T * = TALK. Ask the person to SPEAK A SIMPLE SENTENCE (Coherently) (eg 'It is sunny out today').
R * Ask him or her to RAISE BOTH ARMS .

If he or she has trouble with ANY ONE of these tasks, call the ambulance and describe the symptoms to the dispatcher.

NOTE : Another 'sign' of a stroke is
1. Ask the person to 'stick' out their tongue.
2. If the tongue is 'crooked', if it goes to one side or the other that is also an indication of a stroke.