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I was at the National Book Festival yesterday in Washington DC where several authors including Rick Riordan, John Grisham, Jodi Picoult and the like did book signings and talked to their fans. The event by itself was sort of poorly managed because the management probably did not expect a crowd on such a big scale (the Smithsonian metro station was closed in the afternoon due to too much crowd!).

But all that apart, people who went with the intention of meeting their favourite authors had a successful day, and that was perhaps the only worthy reason to go to the festival because the book festival did not have any book stalls (other than a jam packed Borders tent selling only very specific books).

Anyway, so I wen’t to catch a glimpse of  Rick Riordan since I am an insane Percy Jackson fan.I got to the pavilion atleast 15 minutes in advance while the previous author was still speaking. After some pushing and jostling I finally edged into the tent and escaped the rain outside. There was hardly any place to stand but I positioned myself so that I could operate my camera.

His talk was quite funny in general and he gave his eager fans a glimpse of what is in store for them in the upcoming months:

1. There will a second Camp Half Blood series of books (yes you heard it right!) coming up soon. I forget if he mentioned when it will be out, but he mentioned that there will be more of Percy and Annabeth to come although Percy will not be the main character in the new series and there will be a new generation of demigods. The new series will probably be based on the next big prophecy that we encountered in “the last olympian”.

2. May next year is going to be about Riordan’s next novel that is based on Egyptian mythology. Now that is something that sounds really exciting. Riordan even read the first few lines from this upcoming book that he says is currently with his editor now!

3. Finally he talked about the Lightning Thief movie that is set to release in February next year. He mentioned that the role of Chiron will be played by Pierce Brosnan and that of Medusa will be played by Uma Thurman. Now that is some interesting cast.

Since I am travelling currently, I will upload pictures soon.

As a web developer, I have used ASPNETDB several times to manage the membership and role information for my applications. It has been a while since I have done software development in ASP.NET. So when I try things now, I realize there are several small things that I knew at my fingertips back then, come with a little more effort right now. I hooked up a new application to use the ASPNETDB, and tried to create a new login. I got the error that the username already exists.

This was surprising, because it was a new application. I realized that the application was actually pointing to the same instance of ASPNETDB on my DB server. I knew that there was some way of isolating multiple applications in the same membership database. After a bit of research I recalled out to do it:

In the web.config file, look for the following section:

<membership>
<providers>
<clear/>
<add name=”AspNetSqlMembershipProvider”
type=”System.Web.Security.SqlMembershipProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a”
connectionStringName=”ApplicationServices”
enablePasswordRetrieval=”false”
enablePasswordReset=”true”
requiresQuestionAndAnswer=”false”
requiresUniqueEmail=”false”
passwordFormat=”Hashed”
maxInvalidPasswordAttempts=”5″
minRequiredPasswordLength=”6″
minRequiredNonalphanumericCharacters=”0″
passwordAttemptWindow=”10″
passwordStrengthRegularExpression=”"
applicationName=”/”
/>
</providers>
</membership>

Change the value of the applicationName attribute inside the providers element to then name of your application, and you are good to go!

This is a short post from the Greater Rochester International Airport as I wait for my flight. No other service at an airport makes me happier than free internet. The first time I saw this was when my flight to Memphis was delayed by a couple of hours and I was stuck waiting at Charlotte Douglas Int’l airport. I saw an unusually high number of people using their laptops and somehow got the feeling that there might be internet connectivity. I booted up my machine and to my pleasant surprise, I was right. I was able to establish a secure connection to my school network and get some work done while I waited. For internet savvy people like us, there isn’t really much you can do if you are stuck waiting at an airport, and a free connection just saves your day.

But I was wondering what is it that allows an airport to host a free wifi connection. Large and prestigious airports like the O’Hare Int’l airport at Chicago do not have a free wifi connection. What is it that prevents them from doing so? What is the business model followed at the lesser known airports that lets them provide this service to travellers?

Several weeks ago, I found myself thinking, how I could shuffle a list/array given to me in a random order. This is a typically commonplace thing to do in several applications: online card games, your favourite music player etc.

The interesting thing about this problem is how some naive approaches, even though easy to code and efficient enough, do not achieve the desired randomness.

Lets define the problem: You have an input array which has elements in positions 1 through n. The objective is to produce a random permutation of the array. By a random permutation, we mean to say that each permutation of the array is equally likely. So a truly randomized algorithm will generate each permutation with a probability of 1/n!

The first approach that comes to mind is the naive approach of generating a random number between 1 and n for each element in the array and placing the element at the position indicated by the random number. This could be accomplished by using another auxillary array and placing elements into the new positions generated. The pseudocode could look something like the following:

NaiveShuffle(A[1...n], B[1....n])            //randomly permutes the elements in array A
for i from 1 to n
random <- RandomNumber(1,n)
B[random] <- A[i]
for i from 1 to n
A[i] <- B[i]


The above approach is very crude in the sense it uses an auxillary array and also parses through the array twice instead of just once. Still, the worst case running time of the above algorithm is O(n).

Random(1, n) generates a random number 1 and n (both inclusive). We assume that the random number generator generates truly random numbers in the interval specified. Also, we assume some kind of collision resolution mechanism. We are assuming that this method returns a random number in O(1) time.

All that said, a O(n) algorithm is not bad at all for this purpose. There is only one problem, this algorithm is WRONG! (hah…fat chance, didn’t we name it a naive algorithm?). Why is that? This is because in every iteration, we generate n possible choices. Since there are n such iterations, the total number of permutations generated is n.n.n.n…….n times = n^n

The  total number of permutations possible while shuffling an array is n!. Since n^n is not exactly divisible by n!, there have to be some permutations which appear more frequently than the others (basic pigeonhole principle). Thus this naive algorithm does not generate truly random permutations.

Lets try something else. We generate a random priority between 1 and n^3 the Random(1, n^3)  routine, and assign a it to each element in the array. Then sort the array based on these weights.

e.g. if the original array is A<1,2,3,4> and we generate priorities randomly as P<34,56,8,77>, then when we sort array A based on the increasing order of the priorities assigned using array P, then we get the shuffled array as <3, 1, 2, 4>.

We used the interval [1, n^3] to generate priorities so as to reduce collisions. I will not delve into the correctness of this algorithm. The running time of this shuffling by sorting algorithm depends on which sorting algorithm we use. Typically it is Big-Theta(n lg n).

Another approach to solve this problem, is to shuffle by swapping:
Shuffle[1...n]
for i from 2 to n
temp = Generate(x from 1 to i)
swap(i,temp)

Notice that the interval for generating random numbers keeps decreasing. For the first iteration, there are n choices. For the 2nd iteration, there are (n-1) choices and so on.

Hence the total number of choices generated by this algorithm is: n(n-1)(n-2)…..3.2.1 = n!

which is exactly equal to the total number of possible permutations. Moreover, since we iterate over the array only once, this algorithm runs in O(n) time.

This novel, published in the year 2008 won the Man Booker Prize in the same year. I bought the book out of instinct, although I haven’t had a very pleasant experience with a couple of other books that have won the same prize. Many people said that the books that won this award were difficult to read and not well accessible. One of my friends gave me a very bad review of the book, but I had no choice but to read it since I had already bought it. I approached the book without any pre-concieved  expectations and I was pleasantly surprised. While I did not bother asking my friend why she did not like the book, there are several reasons why I would recommend the book to any reader.
First of all, the book is an effortless read, and the story flows at a good pace. The story is narrated in first person by Balram Halwai, who is the protagonist. It is his account of his rise from lowly origins in a village in rural India amidst crushing poverty where even the basic amenities of life are hard to come by; to his current position as a successful entrepreneur in a big city. But the story is not one of inspiration as one would imagine from such an account. Instead it is a story full of intrigue, corruption and crime, but narrated with an innocent and brutally honest tone that makes you chuckle throughout. The story takes a swipe at the corrupt political system of the country and how the people are forced to play along with it if they want to survive. What moves you while reading this story is how the honest and hardworking village boy is transformed into a shrewd, scheming man who does not hesitate to take the law into his own hands.
Adiga has done a masterful job in this darkly comic debut novel of his with a sharp observation and sardonic voice.

This is Jhumpa Lahiri’s third piece of work (after Interpreter of Maladies and The Namesake). Sticking to her theme, this is also a set of short stories, based on the lives of expatriate Bengali parents and their american-raised children. I used to really want happy endings from books and stories I read. Jhumpa Lahiri is not someone who would give me that. Her stories are colorful, full of real characters that you would come to love; her writing is superlative and flows with an effortless pace; but the stories end abruptly at a crucial emotional juncture when the characters are at some kind of an emotional high point. I am always left wanting for more, but I end up accepting the stories for what they are.
One thing I noticed in her first two works is her brilliant descriptions of food and cooking, so much so that I used to be amazed at her culinary knowledge. I was looking forward to the same, but found that missing in Unaccustomed Earth.
There are two parts in the book: the first one has 4 stories, and the 2nd part has 3 stories. I did not realize till the middle of the last story that the 3 stories in the 2nd part are actually related: based on the same two protagonists. Each story in the trilogy are spaced apart by a number of years .You could call me dim for not figuring this out earlier, but these stories are just like the previous ones, and each one could be read without any bearing on the previous ones, and none of them give any direct indication of a connection, except for the names of the characters (which could have been anything in any of the stories without affecting the plot). The first two parts are narrated by the two individual characters, based around their separate lives. The third story is narrated by the author, linking the two characters together finally. Being a fan of different narrative styles, I loved this.
Finally, Jhumpa proves that she can write not only about life in the US, but also Europe, where a considerable portion of the final story is based.
Brilliant piece of writing. Highly recommended reading.

I recently finished reading One Flew Over the Cukoo’s Nest: by Ken Kesey. This novel has been included in TIME Magazine’s 100 Best English-language Novels from 1923 to 2005.

The novel is based in the mental ward in a psychiatric hospital in Oregon. It is an allegory on the psychopathic obsession of that time (the 1960s). The story is narrated by a gigantic, half-Indian “Chief Bromden”, a patient of the ward who suffers from hallucinations and delusions.The ward is controlled by a tyrannical nurse: Nurse Ratched who reigns over all the inhabitants of the ward, including the orderlies, the staff nurses, and even the doctor. He controls everyone with surgical precision, using underhanded tactics to render everyone helpless and submissive.

Things change with the arrival of Randal McMurphy, a Korean veteral who has a history of insubbordination and street brawls. McMurphy quickly realizes that several patients in the ward are sane and simply emasculated because of the nurse and her controlling tactics.

This novel is about the fight between authority and free spirit.

I started reading this book by Ken Follet over 5 months ago. When I just had a couple of dozen pages left to finish the book, I went away to the US and for some reason I did not carry the book with me. Now that I am back in India for a while, I finished the book today. It is a really big book with over a thousand pages. There are several plots in the story, and like most really long stories, you feel that some of those could have been avoided for the sake of a smaller and crisper story.

The plot of the story revolves around the building of a cathedral in medieval England during the period of civil war and how the lives of several people around the cathedral is embroiled in politics and powerplay. The book spans several years and hence the author has been able to sketch the characters in great detail (no surprise there).

Several  reviews on amazon tout this book as a breakthrough in the historical fiction genre, which I think is a bunch of nonsense (no wonder since the book was a part of Oprah’s book club). I don’t really have good things to say about Oprah’s book club and I would probably have not picked up this book had I known earlier, but the book did turn out to be entertaining, with a lot of gratuitous sex and violence thrown in. Sometimes it drags simply because the plot is very twisted and long.

I did learn a bit about medieval architecture, cathedrals, clergymen, nobles and the like. All in all, I recommend this book for a one time read. Entertaining, but long.

I have always derived pleasure writing programs that solve real world problems. This is one such problem that I was able to solve. With the holiday season on, you might want to send greetings to your numerous business contacts. If you have several contacts that you want to send personalized messages to, then you very well can imagine how much time and effort that will take.
So this is what I set out to do: create an application that would send out emails to several contacts, with a personalized greeting line, but similar message body. Also, depending on the type of contact, you might want to send a different message. E.g. if it is a close colleague of yours, then you might want to send a more personalized mail rather than a one liner. Since these are personalized emails, these need to be sent from your actual email id rather than an SMTP server on your dev machine. Also, I needed this application to work for someone else who runs only MS Office on his machine. So I decided to use Microsoft Office Outlook 2007 for this task.
The first thing to do was to decide the fomat in which I would store all the configuration information that would be used by the application: So I created two different text files, mail1.txt and mail2.txt each with a separate email message:

Hello {0}
Mail body

Where {0} is a placeholder that will be replaced by the receiver name. mail1.txt and mail2.txt have the same structure except for the mail body depending on the requirement.
Next, I needed to create a list of names and the corresponding email IDs to which the mails are to be sent. Also, I needed a flag that will indicate the type of message that is to be sent, i.e. mail1 or mail2. I created a comma separated file with the following format:

<Receiver’s name>, <email id>, <mail body to be sent, i.e. 1 or 2>

I wrote a console application in C# that uses the Microsoft Office 2007 Primary Interop assemblies to automate sending emails to all these contacts specified. The emails get sent using the default account configured in your Outlook. The code looks something like the following. Please note that this is a quick hack which actually works and that I have not really done a lot of error handling or exception management on this because I know the conditions under which this will be used.

Microsoft.Office.Interop.Outlook.Application app = null;
Microsoft.Office.Interop.Outlook._NameSpace ns = null;
Microsoft.Office.Interop.Outlook.PostItem item = null;
Microsoft.Office.Interop.Outlook.MAPIFolder inboxFolder = null;
Microsoft.Office.Interop.Outlook.MAPIFolder subFolder = null;
Microsoft.Office.Interop.Outlook.MailItem memo = null;
Microsoft.Office.Interop.Outlook.MAPIFolder sentFolder = null;
StreamReader addressReader = null;
StreamReader contentsReader = null;
StreamWriter logWriter = null; 

try
{
addressReader = new StreamReader(ConfigurationManager.AppSettings["addresses"]);
String currentLine = String.Empty;
String[] currentReceiver = null;
String messageBodyFile = String.Empty;
logWriter = new StreamWriter(Path.Combine(Environment.CurrentDirectory, "Log.txt"), false);
while (!addressReader.EndOfStream)
{
currentLine = addressReader.ReadLine();
currentReceiver = currentLine.Split(',');
switch (currentReceiver[2])
{
case "1":
messageBodyFile = ConfigurationManager.AppSettings["contentsFile1"];
break; 

case "2":
messageBodyFile = ConfigurationManager.AppSettings["contentsFile2"];
break; 

default:
Console.WriteLine("Could not send email to ", currentReceiver[0]);
logWriter.WriteLine("Could not send email to ", currentReceiver[0]);
currentReceiver[1] = String.Empty;
break;
} 

#region EmailInit 

app = new Microsoft.Office.Interop.Outlook.Application();
ns = app.GetNamespace("MAPI");
ns.Logon(null, null, false, false);
sentFolder = ns.GetDefaultFolder(OlDefaultFolders.olFolderSentMail);
memo = (Microsoft.Office.Interop.Outlook.MailItem)app.CreateItem(OlItemType.olMailItem); 

#endregion 

contentsReader = new StreamReader(messageBodyFile);
memo.To = currentReceiver[1].Trim();
memo.Subject = ConfigurationManager.AppSettings["mailSubject"].Trim();
memo.Body = String.Format(contentsReader.ReadToEnd(), currentReceiver[0]);
memo.BodyFormat = OlBodyFormat.olFormatHTML;
memo.Send();
Console.WriteLine("{0}: Sent email with body {1} to {2}:{3}", DateTime.Now, currentReceiver[2], currentReceiver[0], currentReceiver[1]);
logWriter.WriteLine("{0}: Sent email with body {1} to {2}:{3}", DateTime.Now, currentReceiver[2], currentReceiver[0], currentReceiver[1]);
contentsReader.Close();
contentsReader.Dispose();
}
} 

catch (System.Exception ex)
{
Console.WriteLine(ex.ToString());
EventLog.WriteEntry("Email Automation", ex.Message, EventLogEntryType.Error);
} 

finally
{
ns = null;
app = null;
inboxFolder = null;
addressReader.Close();
addressReader.Dispose();
logWriter.Close();
logWriter.Dispose();
}

So, I vented my anger by writing a blog-post about the latest terror attacks. Apparently the NSG has flushed out the scum from the Taj hotel. Things are going back to normal. I have not watched the news since the evening of the ill fated day (EST). One of the questions I asked a couple of questions in that post was:

“What can we as citizens of a civilized society do to protect our interests? The cause of these terror attacks are varied in various places, but it is innocent people walking on the street who bear the brunt (and the people who go out to fight for us)”

And I have been thinking about this on and off. I have asked this question to several people. I am just plain baffled by the lack of responses or ideas. Varish said that it is time for the political system of the country to start acting tough. Really? Is this the time for the gov to start acting? The government should have acted way too long ago. Anyway, that is not even the point.

We all have conceded at some point that the government of ours is not doing much other than condemning the attacks and making vain platitudes. The dirty politicians will even turn this to their advantage so that they can gain political mileage for the upcoming general elections.

All right! Enough trash talk. We know that the government is not doing what it is supposed to. So I ask the question again. What do WE do? We are the educated elite of the country. We cast those votes. We elect those representatives. Is there something we can do to help? I feel we are totally lost on that question.

I suggested doing a signature campaign amongst the student and young professional networks in and out of India. We could send those signatures with a message to our respected Prime Minister. My good friend asked me whats the point behind a signature campaign? I said, “we need to make sure that the government understands that the educated elite of the country, both in India and abroad needs to see some real action now, and not just empty promises.”

Then he asked me a question to which I did not really have an answer: “Doesn’t the government already know that it has to battle terrorism?” . Just that any Indian government does not have the guts to take the right steps which are against their own self serving motives. And even we the people are to blame. Everytime there is an attack on teh city, we say that Mumbai is unbreakable. We are the most resilient city in the world. Hell we don’t want to be resilient! Why is it that all these pains and agonies are forgotten a couple of days after the bloodstains have been washed? The sacrifices of the security forces and the pains of the people disappear into oblivion and we settle down into our old routine. This continues till the time there is another attack. Oh yes, don’t be fooled into thinking that they are done.

So I was set into thinking what would the damn signature campaign achieve? It would probably serve the purpose to make it clear to the government that we are pissed off. But doesn’t the gov already know that? Like Jayu said “they cannot be that detached from public sentiment”. So how do we make them do it? In an ideal democracy (oh and we are very proud of the fact that we are a democracy) the people are able to hold the gov accountable for their actions and inactions. Why can’t we do that in India?

“Electoral power is supposed to be the form of public control over its govt in a democracy. Here it gets sold for free sarees and rice during election time. The educated middle class has a very small say in the overall process.”

So this is my sincere message to everyone reading this post. This general election, PLEASE GO AND VOTE. Cast a responsible vote. Our only goal should be to cast aside all our feelings of mutual distrust and communal agendas and questions of religion and reservation, and elect a government that would actually ensure that our people don’t get slaughtered on their own street.

The only other weapons that we have are the RTI and the PIL. But only the legislature has the right to ammend the constitution. The courts can only direct the legislature to do something. So let us wield the only real weapon we have. The right to vote. Let the current government understand that they have to prove a point to us, and that we are watching. And let them consider this a threat: we will not vote for you if we do not see results.

Note to all the readers: If you have any ideas, post a comment.