Hai Friends...

JConqurr - Multicore Programming Toolkit For Java

2011-01-22T20:51:00.003+05:30

Our final year project research paper is got published in The International Journal of Computer and Information Engineering WASET(http://www.waset.org/journals/ijcie/).
You can download the research paper by clicking the following link.

http://www.waset.org/journals/ijcie/v3/v3-4-34.pdf

I would like to thanks my group members Madhawie Samaranayake, Lahiru Suranga Bandara, Lasantha Fernando and the project coordinator Mr Kishan Wimalawarne for this achievement. success.

Analysis of Parallelizing the Fibonacci using java executor framework

2010-03-20T21:07:00.006+05:30

From my last post I have showed you a mechanism that we can used to parallel the Fibonacci. From this post I hope to analyse the various mechanism that can use to parallel the Fibonacci using java and I'll point out the some of the disadvantageous.

One of the famous book in parallel computing is "The Art of Multiprocessor Programming" by Maurice Herlihy and Nir Shavit. In the book we can found a one mechanism that used for parallel the fibonacci.In achieving that the author has used the java executor framework. Here is the code used in the book.

According to the algorithm it mainly focus on the finer-grained parallelism. So when the Fibonacci number increases, number of task increases. So lot of overhead will added in resource allocation for each new task. When you using java threads or the java executor framework if you targeting a performance gain then the time taking for your algorithm complexity must be above the time which require in resource allocation of threads or the executor framework. So what you should focus is achieving the coarse gain parallelism as much as you can. Also you must consider the number of processors in your machine. Your coarse grain parallelism must build around those processor. That's the thing which I did exactly in my algorithm. Which is shown below.

According to the above mechanism resource allocation happens only for two tasks. So those two task bare equal amount of load. When you fork the problem no need to fork it too much. The amount of forking level must depend on the number of processors. That will give you a big performance hit. This is a common practise that we need to adhere in parallel computing.

Parallelizing the Fibonacci using java

2010-03-20T02:43:00.011+05:30

Hai...

Its being a quite some time to my last post. Anyway since I currently researching on parallel computing I thought to publish a post relevant parallel programming. So I thought to implement the Fibonacci calculation algorithm in a parallel way using Java. Here is the source code.

Parallel Fibonacci--------------------------------------

Sequential Fibonacci----------------------------

I have use the Java executor framework to achieve the parallelism. I tested the source code under duel core 1.73Ghz machine. Following are the results that I got for sequential and the parallel computations.

number=25
seq=0.0040 parallel=0.0070
number=30
seq=0.035 parallel=0.029
number=35
seq=0.215 parallel=0.189
number=40
seq=2.025 parallel=1.719
number=45
seq=22.215 parallel=14.291

Above graph shows the performance of each calculation (X=fib number,Y=time(s)).

Thats it for today. I hope to explain the concept behind the performance gain in next post.

How to use OpenForecast to a add forecasting features to you web applications...

2009-12-27T18:32:00.008+05:30

Forecasting is one of a nice feature you can add to your data related web application.Assume we have to predict a measurement of a temperature for a given place and date. For that we required a data mining tool. So we achieved this task by using an open source forecasting library called OpenForecast. The advantage of the library is it provides lot of scalability our application. So we can add any data field for our prediction. Below I mentioned the approach we used to achieve the forecasting using OpenForecast.
• First you have to define the test data set for the forecast. For that library provides two class called DataSet and Observations.
• Using Observations class we can define the past observations we made. Then we have to assign the each Observation objects to the Data set. A sample code is shown below

// Create Observation for temperature measured on 2009/12/20
Observation observation1 = new Observation(32.0);
observation1.setIndependentValue("year",2009);
observation1.setIndependentValue("month", 12);
observation1.setIndependentValue("date", 20);

// Create Observation for temperature measured on 2009/12/21
Observation observation2 = new Observation(30.0);
observation2.setIndependentValue("year", 2009);
observation2.setIndependentValue("month", 12);
observation2.setIndependentValue("date", 21);

// Create Observation for temperature measured on 2009/12/22
Observation observation3 = new Observation(27.0);
observation3.setIndependentValue("year", 2009);
observation3.setIndependentValue("month", 12);
observation3.setIndependentValue("date", 22);

DataSet dataSet = new DataSet();

// Add Observations to the DataSet
dataSet.add(observation1);
dataSet.add(observation2);
dataSet.add(observation3);

• After we define the test data set as above we have to use a forecast model to test the data set. For that the library provide a functionality called getBestForecastModel(DataSet dataSet). So we pass our data set and get the best forecast model that can use to train our data set. Library has set of forecasting models such as Double Exponential Smoothing Model, Multiple Linear Regression Model, Naïve Forecasting Model, Polynominal Regression Model, Simple Exponential Smoothing Model, Triple Exponential Smoothing Model, Weighted Moving Average Model. To train the dataset we call the model.init() method. Following code shows this mechanism more clearly.

ForecastingModel model = Forecaster.getBestForecast(dataSet);
model.init(dataSet);

• Then we have to create another Observation/DataPoint for our prediction. In there we set the value to zero and add other independent variables. After that we have to create a new data set and we add above Observation/DataPoint object to our new data set. Sample code shown below.

DataPoint fcDataPoint4 = new Observation(0.0);
fcDataPoint4.setIndependentValue("year", 2009);
fcDataPoint4.setIndependentValue("month", 12);
fcDataPoint4.setIndependentValue("date", 23);

// Create forecast data set and add these DataPoints
DataSet fcDataSet = new DataSet();
fcDataSet.add(fcDataPoint4);

• Now we have created the data set which we want to forecast. Next we forecast the data set using our model and we get the dependent value from above fcDataSet like below. Our forecast result is equal to the value return by the getDependent() method.

Iterator itt = fcDataSet.iterator();
Double value=0.0;
while (itt.hasNext()) {
DataPoint dp = (DataPoint) itt.next();
double forecastValue = dp.getDependentValue();
value = forecastValue;
}

OpenForecast Site:http://openforecast.sourceforge.net/
Download OpenForecast:http://sourceforge.net/projects/openforecast/files/OpenForecast/OpenForecast%200.4.0/OpenForecast-0.4.0.jar/download

Patterns in Parallel Computing - Task Decomposition Pattern in a nut shell

2009-11-03T14:16:00.005+05:30

In parallel programing we can find patterns that can use to achieve the parallelization. Here I listed the patterns that used in parallel programing.

Task Decomposition Pattern
Data Decomposition Pattern
Group Task Pattern
Order Task Pattern
Data Sharing Pattern
Design Evaluation Pattern

Task Decomposition in a nut shell...

When achieving task based parallelism programmer must aware about the following points

He must understands the which are the computationally intensive parts of the problem.

Key Data structures
How the data is used as the problem's solution unfolds.

Fundamentally every parallel algorithm involves a collection of tasks that can executes concurrently and the challenge is to find those tasks and crafts an algorithm that lets them run concurrently.It will be easy to achieve task based decomposition when it is set of independent task.

Lets' see what are the factors which influence in parallel design

Flexibility : Allow to adapted to different implementation requirements.
Efficiency : Parallel program must scale efficiently with the size of the parallel computer. Ex: Task decomposition needs to keep all the PEs busy.
Simplicity : Task decomposition needs to be complex enough to get the job done.

In a task based decomposition we look at the problem as a collection of distinct tasks paying particular attention to

The actions that are carried out to solve the problem.
Whether these actions are distinct and relatively independent.

Tasks can be found in many different places.

Each task corresponds to a distinct call to a function defining a task for each function call... leads to what is called a functional decomposition.
Distinct iterations of the loops with in an algorithm.
A large data structure is decomposed and multiple units of execution concurrently update different chunks of the data structure. In this case the tasks are those updates on individual chunks.

Matrix multiplication
When we consider a multiplication of two matrices A and B(C=A.B). We can produce a task based decomposition by considering the calculation of each element of the product as a separate task. Each task needs to access to one row of A and one column of B. All tasks are independent. Also all the data that is shared among the tasks A and B is read-only. That mean an implementation of a shared memory environment.

But this algorithm has a poor performance because the memory access time is slow compared to floating point arithmetic. Bandwidth of the memory subsystem would limit the performance.

But we can design a algorithm that maximize the reuse of data loaded into a processor's caches. This can be achieved by two different ways.

Using the Group Tasks Pattern: tasks which use similar sort of elements are grouped and run on the same UE.
Data Decomposition: Design the algorithm from the beginning around the way the matrices fit into the caches.

Most of the cases we will use the Task decomposition with the conjunction of Group Tasks pattern and Data decomposition.

Jargon Used in Parallel computing

2009-11-01T13:42:00.003+05:30

When we studying on the parallel computing there are set of terms that will we use frequently.In here I have listed some of the terms used in parallel computing...

Task: Task is a sequence of instructions that operate as a group ex:multiplication of sub elements in a matrices,inner products between rows and columns f the matrices or individual iterations of the loops involved in the matrix multiplication.

(UE)Unit of Execution:Generic term for one of a collection of possibly concurrently executing entities,usually either process or threads. A Task needs to be mapped to a UE such as a process or a thread. We can say that "thread" is the fundamental UE in modern operating systems.

(PE)Processing element:Term for a hardware element that executes a stream of instructions.

Load balance:How well the work is distributed among the PEs.

Load balancing: process of allocating work to PEs,either statically or dynamically.

Synchronization:Task scheduling and other factors in parallel program can not be determine early. So Synchronization is use achieve the ordering of the task when is it necessary.

Race conditions: Is a result from errors in synchronization. Occurs when the outcome of a program changes as the relative scheduling of UEs varies. Because the scheduling of the UEs done by the OS. Race conditions are difficult to debug. Because its happens randomly. We can not reproduce as we want.

Deadlocks:occurs when there is a cycle of task to in which each task is blocked waiting for another to proceed. Like wise every one will wait for each other forever.

Purpose of the Multi-core programing tool kit for Java

2009-07-06T23:12:00.005+05:30

Multiprocessor programming is one of the popular research areas developing in
modern computer era. Even though modern computers come up with Multiprocessor facilities most of the current programming languages like Java do not have good supporting tools.
So the purpose of the project is to provide a tool kit which support multiprocessor programming for Java. When doing research for the project we had found some similar systems which provide multiprocessor programming support. Cilk is one of the systems which support the multiprocessor programming support for C language. Also TBB (Threading building blocks) is an API which supports multiprocessor programming for Java. But the main
drawback of the above systems is that the developer must be aware of multiprocessor programming techniques.

From this “Multi-core programming tool kit for Java”, any developer who does not know about multiprocessor programming can enhance the quality of their code and make it run much faster. Our project aims to develop a tool-kit that would enable the programmer to identify sequential code segments that can be converted to harness the capabilities of a multi-core environment and would also optimize and convert the code such that parallel computing capabilities would be utilized. Also as a part of the tool-kit, the capability to convert traditional lock-based data structures into non-blocking (lock-free and wait-free) would be provided where such optimizations are possible. Also cache optimizations would be given. The plug-in would be developed for a java IDE that provides the above capabilities with other features such as performance analysis, code optimization and automatic code
conversion.

Multi-Core programming toolkit for Java

2009-07-04T13:43:00.003+05:30

Multi-core programing is one of the biggest research area in modern computer era. Through this project I hope that our project team can contribute lot to the Java developers around the world. Currently we are working on the project proposal and doing the literature survey.
Our team would like to thank Mr Krishan sir for giving this idea for our final year project. This project will touching the best areas of the computer science like Compiler theory,Concurrent and Parallel programing, Java Threading etc...
So this will be a tremendous experience for all of us.

Project members:
Lasantha Fernando: Project leader
Lahiru Suranga
Madhavi Samaranayake
Chathura Prabuddha Ganegoda.

How to intgrate Adscene with your blogger

2009-05-08T14:03:00.000+05:30

How to create a simple Maven project

2009-05-07T19:47:00.008+05:30

Execute the following command where you want to create the project.

mvn archetype:create -DgroupId=com.yourcompany.app \-DartifactId=myApp

After you execute the command you will get directory structure like below
src Directory contains all of the inputs required for building,documenting,testing and deploying the project

click on the image to shrink.

Good luck.

Design Principles

2009-05-07T19:23:00.003+05:30

Hai...
These are the most important design principles that we have to keep in mind when we doing the development.

Identify the aspects of your application that vary and separate them from what stays same
Program to an interface not an implementation
Favour composition over inheritence
Strive for looslycoupled designs between objects that interact
Classes should be open for extention close for modification
Depend upon abstractions.Do not depend upon concrete classes
Only talk to your friends (To maintain low level of coupling)
Don't call us we'll call you (Super classes runing the show)
A class should have only on reason to change

Good luck...

Significance Of Component Base Architecture

2009-04-27T10:09:00.002+05:30

Hai Friends
I thought to share this presentation with you. I did this presentation as a gift to my Teamwork Java Team.
click here to download it.

How to create a JIRA patch using Eclipse Ganymade

2009-04-27T00:24:00.010+05:30

Hai...

First you need to have subclipse installed in your Eclipse Ganymade.
Then check out the source code from the repository.
After you worked on the JIRA issue, right click on the project root and select team.Then select the create patch. Then you will get three options. Based on your requirement select the option.

This will do the differentiation with the original code base and generate the patch.txt. You will get a option to point the location that you want to save the patch.

This is the easiest way to create the patches.

So good luck.
Happy coding...

How to release your stress....

2009-04-01T10:00:00.006+05:30

For all the Gsocers

Its normal that your a in a great stress when dealing with a world class company. The best thing you can do is to release you stress by talking to a great person you know.Specially a person having a MBA.
because they can understand you in a minute.
So calm down. Get a great guidence.
Good luck.

Special thanks to.
Mr Gunasiri.
CEO of the Teamwork Technology
Sri Lanka.

Great Thoughts of Donald J Trump.....

2009-03-31T11:46:00.002+05:30

Be a General
Stay Focused
Maintain Your Momentum
Get a Great Assistance
Don't Equivocate
Every New Hire Is a Gamble
Ideas Are Welcome, but make sure You Have the Right One
Focus on the Talent instead of the Title
Manage the Person, Not the Job
Keep Your Door Open
Think Big and Live Large

Good luck...
Just practice it as you can....

Xwiki Enterprise design Mockups......

2009-03-30T01:38:00.006+05:30

Hai friends...

This is the best thing to do. To get a good understanding about the data model of your application.
Even If you not doing a Xwiki project UI is the best place to start.
Any way with the component based architecture this is the best thing to do.....
Ok you better have look at this.

Then you can get my mockups from here.
This will give you some ideas for your application.

Good luck...
Hope to give some introduction in component base architecture....

Special thanks for Survey Application mentors:Ludovic, Serigue

SIGNIFICANCE TESTING

2009-03-29T06:36:00.002+05:30

Null & Alternative Hypothesis

When making a statistical enquiry,we often put forward a hypothesis concerning a population parameter.For example.

The mean height of 15-year-old girls is 1.62
The proportion of left-handed people is 0.95

This hypothesis called the null hypothesis and is denoted by (H0)

In order to test the validity of H0, we consider observations made from random samples taken from the population and perform a statistical test.
If this test shows that we should reject null hypothesis,H0,we do so in favour of an alternative hypothesis,denoted by H1.

Abstraction Of The Xwiki Todo tutorial....in my view point

2009-03-28T15:09:00.003+05:30

Hai
You better do the tutorial before studying this.
Also give me feedback if I wrong...
This is what I see......
And sorry about my hand writing....

Good luck.

Funtional Architecture Of The Xwiki Survey Application

2009-03-27T19:16:00.003+05:30

Hai All The New Comers To FOSS & GSOC.....

Ok If your a new comer to GSOC or FOSS like me I know your in a trouble thinking hard what to do for the this topic
Please describe a tentative project architecture or an approach to it:

Ok Xwiki has very good architecture.You will take some time to understand that. Best thing you can do try to build the functional architecture sort of thing while studying the Xwiki architecture.
That will give a lots of confidence to you.

Thank you.
Good luck...

How to Use IRC channel to make your GSOC projects success

2009-03-26T14:02:00.006+05:30

This is what I had learned...
Ok Guys Here We Go.............

Try to be online at every time as you can.
Watch the chat discussions going on.
Wait for right moment to ask it.
If you have any question first do a google search.
Then try to ask it from a friend(GSOCER) not from a developer.
Then If you cant find the answer just ask them dont try to make the conversation too long because you are using the time of the others too....
If you are not hurry best thing to do is send a message to mail list.

Also this will be useful too.....(Thank you Charith)
Ok good luck for all the g soccers

[FATAL ERROR] org.jvnet.jaxb2.maven2.XJC2Mojo#execute()

2009-03-24T09:28:00.002+05:30

Ok

I had faced lot of trouble while i building the Xwiki platform using maven version 2.0.9
While running the build it gives me a
[FATAL ERROR] org.jvnet.jaxb2.maven2.XJC2Mojo#execute()
So I used the new version 2.1.0 of maven which has fixed this bug
Make sure to properly install your mvn 2.1.o version

good luck

Increase Memory In Maven(Windows users..)

2009-03-24T09:23:00.003+05:30

Configure your Environment Variables as follows

Variable Name:MAVEN_OPTS
Variable Value:-Xmx1024m -XX:MaxPermSize=128m
then simply build the application

good luck....

How To Align Struts 2 Checkboxes Vertically

2009-02-13T09:05:00.000+05:30

You Have to override the checkboxlist.ftl. There is a tag called <input type="">wrap that tag with <tr> </tr> tags.Then you can align the checkboxes verticaly.

Checkbox list problem in Struts 2

2009-02-13T07:20:00.000+05:30

I had faced a problem using s:checkboxList in a delete multiple entries from a table. But I was able to find a way to delete multiple rows in a table using s:checkbox . Only few steps you need to do.

First you have to create a list in the Action class.It has to be type of "String" list.Lets say I add string array called "String[] userIds" and the getters and setters for it.
Then how we can input list of checkboxes in to a table using struts 2.I used the "s:iterator " tag for that
You need a list for the "s:iterator" tag.In my case lets say List<"type"> users=New ArrayList<"type">(); which has id,name,email,mobile... like properties.Then insert a check box inside a tag.And your check box name has to be the name of the above string array name"userIds".Your code should look like this after that
s:iterator value= users" status="count">
userIds" cssClass="checkboxSelect" fieldValue="%{getId()}"
theme="simple"/>
Then I used a checkbox to select/deselect the list of check boxes in the table. I added the following check box in the column head
s:checkbox name="selectAll" cssClass="checkboxSelect" onclick="checkAllElements(document.deleteMultiple.selectAll);"theme="simple" "/>"
In here "deleteMultiple" is the name of the html form.
Then about the "onclick" function you need a javascript to select all the checkboxes in the table rows.
"function checkAllElements(toggle) {
//checking all checkboxes in the data rows
var elements = document.getElementsByName("userIds");
if (elements && elements.length > 0) {
for (var i = 0; i < checked =" toggle.checked;" headerelements =" document.getElementsByName("> 0) {
for (var i = 0; i < checked =" toggle.checked;">
Rest is upto you.....(action mapping and action implementation ex:add a delete button and submit the above form to delete rows.In struts xml map the action with the class and implemet the delete method according to your application)