Alexander von Humboldt
1769- 1859 “Make the most of yourself, for that is all there is of you.” - Ralph Waldo Emerson  . I tried GTD a looooong time ago and I gave up almost immediately. It surprises me though, that there is actually an outlook plugin for GTD system and a ton of softwares based on GTD. That means there is some section of people who are finding it useful .
Anyways this book is markedly different in its premise. It is based on chunking principle. If you want to do anything , focus on it for a specific period of time, take a break and repeat it !!. Via Siddharth: [vimeo 24302498 w=400 h=225] “The plural of anecdote is not data.” - Roger Brinner  
To visualize data efficiently, one must make a transition from a state where you use point and click interfaces (a user’s view) to a state where you can code your own graphic( a developer’s view). At the outset, “User’s view” is very appealing as you can use a cutesy GUI to draw some graphs etc. However if you have discover something in the data, this “User’s view” is of no use and one needs to acquire developer skills to visualize graphics. The book is about a package “grid”, written by Prof.Paul Murrell. Well, one might think that base graphics is good enough. Why go in for grid ? Well, the power of grid lies in the fact that it gives complete control of various graphic elements, their position and their characteristics. Let’s say you have a scatterplot which is produced by base R. By using Grid package, you can rebuild the entire graphic piece by piece. This in itself is not the purpose of grid package, but it shows that any graphic that you have seen in base graphics/ lattice can be updated, created, modified at your heart’s content. This book gives a very detailed description of the grid package to create and explore various graphics. 
One of my favorite quotes about writing/composition is, “We write to know about that which we know” - Grace Paley By writing down the stuff that you have in your mind, you bring some structure in to your thought process and this structure in turn helps you think better. Most of the times there is an internal editor in our mind which kind of censors our thoughts in forming connections. As everyone knows, the best ideas usually arise by combining themes from seemingly diverse fields. I guess this internal editor hinders us from connecting stuff unless we overwhelm it with some kind of constraint / create a situation where its power becomes shallow. There are many ways to escape from this internal editor.Is it any wonder that some of the best ideas we get are when we are away from work ,be it traveling/ running / playing some sport/ relaxing and thinking freely outside of our work / debating about something with a friend, etc. Internal editor is damn good when we are planning to execute stuff. But to ideate, I guess one must seek activities that are far removed from the work context. What does this book say ? Well firstly, something about the title. The author is a positioning consultant and no wonder the title smells like a marketing ploy. The book is about writing and a particular form of writing called FREEWRITING. What is freewriting ? Freewriting is a certain style of writing that we can use to get all our random/chaotic/semi-structured/exploratory thoughts on paper without our internal editor coming in our way. “ We do no market research . . . We figure out what we want.”
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- Steve Jobs_ I was introduced to writing math at a very late stage of my education. Somehow math meant solving bunch of problems, understanding theorems / proving theorems or translating math problems in to an algorithm that could be solved numerically on a computer. What has “Writing”, as in writing in plain English got to do with learning mathematics ? My first brush towards this activity happened accidentally while I was teaching as an adjunct. One of the senior lecturers was preparing an assignment for the class with no problems/no equations to solve / nothing to calculate. I was curious about the assignment and asked her , the reason for giving such an assignment. That’s when I learnt that there is a ton of stuff that can be learnt about math, by writing about math in one’s own words. What are the kinds of writing that can be done ? A riveting talk given by Prof. Rajesh Rao on using statistical models to decipher Indus script http://video.ted.com/assets/player/swf/EmbedPlayer.swf Stumbled on to this piece via 13 Writing Tips- Chuck Palahniuk :
Twenty years ago, a friend and I walked around downtown Portland at Christmas. The big department stores: Meier and Frank… Fredrick and Nelson… Nordstroms… their big display windows each held a simple, pretty scene: a mannequin wearing clothes or a perfume bottle sitting in fake snow. But the windows at the J.J. Newberry’s store, damn, they were crammed with dolls and tinsel and spatulas and screwdriver sets and pillows, vacuum cleaners, plastic hangers, gerbils, silk flowers, candy - you get the point. Each of the hundreds of different objects was priced with a faded circle of red cardboard. And walking past, my friend, Laurie, took a long look and said, “Their window-dressing philosophy must be: ‘If the window doesn’t look quite right - put more in’.” http://www.vcasmo.com/swf/vcasmo.swf Key Steps : - Did not use R for data import operation - Used SPSS to read the data
- Feature Selection - Used R in this step
- Data Cleaning - Treatment of Categorical variables was a problem
Software used : SAS + R Techniques used : Gradient Boosting machine(gbm package) Rationale : - Handling of missing values
- Robustness against extreme values
- Handling categorical and continous variables
- Models interaction between predictors
- Can model nonlinear dependencies
Fitting Time : Couple of hours on a desktop “ The act of arranging information becomes an act of insight. ” - Edward Tufte “ When that time comes, I try to be alone and silent for several hours; I need a lot of time to rid my mind of the noise outside and to cleanse my memory of life’s confusion. I light candles to summon the muses and guardian spirits. I place flowers on my desk to intimidate tedium and the complete works of Pablo Neruda beneath the computer with the hope they will inspire me by osmosis. If computers can be infected with a virus there’s no reason why they shouldn’t be refreshed by a breath of poetry. In a secret ceremony I prepare my mind and soul to receive the first sentence in a trance, so the door may open slightly and allow me to peer through and perceive the hazy outlines of the story waiting for me.”
Books on R are tricky to read especially when the sheer amount of things that R can do is mind-boggling. So, there are books that range from very specialized to very generic and there is no choice but to refer this gigantic range of collection based on one’s needs. The flip side to this vast amount of stuff is, “it is likely that a first timer would fail to see the forest for the trees”. 
It has started raining in Mumbai and the pleasant climate after three months of scorching heat, enlivens the spirit. Will attempt to write a few words about this book. Since I have been staying alone for the past few years in Mumbai, I have gone back to “Sitar” which I could not practice in NY for a couple of reasons: Firstly, I missed the space needed for practicing any instrument. Staying with two other guys in a flat was not particularly conducive to playing an instrument without distractions. You have to actively seek out “No Distraction time” so that you don’t cause any distraction to others -:) . Well, work + academics + programming left me with little energy to pursue “Sitar”. Secondly, I could not afford a teacher. Self-study / Self-training in any field requires you to be skillful up to a certain level/ be an apprentice for some time, after which you can be in a cruise-control mode in exploring stuff. I wasn’t anywhere close to that stage and a Sitar teacher was imperative to my practice. Some quick calls to a craigslisters revealed that they were too costly for me to even think of regular classes. Thanks to my decision to head back to India, I found two things in my life needed to play any instrument, a certain level of solitude & a teacher. The former, I deliberately opted for (don’t know how long I can be in this state), the latter,”finding a teacher”, happened out of a chance conversation with someone.  
A classic is a book that has never finished saying what it has to say – Italo Calvino. These words definitely apply to Feller’s books. Both the volumes by Feller on probability can be considered as classics. The first book deal with the discrete variables while second is far advanced as it deals with measure theory and continuous variables. Markov processes are one of the main sources for Martingales and I had to go back to Feller to work on Markov Processes and managed to go over the entire book instead of only looking up stuff on Markov Processes. Let me attempt to various probability topics that are covered in Volume I. This post is going to serve mainly as my reference to various ideas and thoughts that the book brings out. This is definitely one of the longest posts that I have written till date. It is a ~5500 word summary and hence this post will definitely have a list of some of the powerful ideas in probability. Everyday you don’t practice you’re one day further from being good - Ben Hogan(golfer) 
The story is about an old professor and a special bond that develops between the professor and his housekeeper. The professor has a peculiar problem that he cannot remember anything beyond 80 minutes. His memory loss caused by a certain accident in his middle age leads to a strange life that he leads. Since he cannot remember anything beyond 80 minutes, he is forced to write short notes and pin it up on his suit so that he can glance at them everyday and remember stuff. His sister-in-law generously takes care of him and provides him with basic amenities like food , shelter and a study room. The professor despite his old age continues doing math. To take care of the cooking,cleaning and other household activities, his sister-in-law appoints a housekeeper. Colin Hughes shares his story on “why he built Project Euler? ” - It should be Playful, bottom-up learning
- Programming is addictive and you can get feedback on customizing other’s code.
So, the code for becoming good at a language is –:) do ( i <- 1
for ( i in 1:N ) print( “ You will fail ” ) ;
i <- N+1
if ( i == N+1 ) print ( “ You will crack it ” )
“ Parenthood is the opiate of the masses ”
- Chuck Palahniuk( Author of “Choke” ) Spot on , as far as India goes –:) . Loneliness is the poverty of self; solitude is the richness of self. - May Sarton 
This book is an awesome resource for understanding finite Markov chains. The book is written in Pre-Latex era and hence one has to struggle to follow the notation. Is the Struggle worth it? IT IS, if you are looking at developing a Matrix perspective towards “Discrete Stochastic Process”. IT IS NOT, if you are looking at quick and dirty formulae. The first version of the book appeared in 1960 and second version in 1976. I wasn’t even born when these books came out –:) . However like many things in life, things that age have their own charm. The book serves as a precursor to understanding Markov chain Monte Carlo method which is an essential tool for any quant.
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![image_thumb[1]](/2011/09/18/markov-chains-summary/images/image_thumb1_thumb.png "image_thumb[1]")
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. The happy puppies are named Prior, Likelihood, and Posterior. Notice that the Posterior puppy has half-up ears, a compromise between the perky ears of the Prior puppy and the floppy ears of the Likelihood puppy. The puppy on the back cover is named Evidence. MCMC methods make it unnecessary to explicitly compute the evidence, so that puppy gets sleepy with nothing much to do. These puppy images basically summarize the essence of Bayes’ and MCMC methods.
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