10,000 finance job cuts forecast

Here we go: 10,000 finance job cuts forecast.

It is only the beginning...

Interview Question Cont'd

Another one I was asked... was about sorting... specifically Merge Sorting.
The last time I wrote a sorting algorithm was ages ago... like in 1994 to be exact.

All those years I have been using libs (JDK, STL) to do this for me...

So for your next interview... Read Sort Algorithms to refresh your memory, and understand (ie memorise) the pseudo-code for Quick Sort and Merge Sort and their related complexity...

I am still not sure what interviewers expect you to be?
To understand things or to know things? To be able to solve problems, or just know the solutions to problems? Being able to do everything from scratch in your head, or spend time doing some research?

The Man Who Loved Only Numbers

Another great book I am reading: The Man Who Loved Only Numbers: Story of Paul Erdos and the Search for Mathematical Truth

Nicely written.

Hedge Fund Interview Question

I went for an interview in a hedge fund... and failed miserably... I did not remember the Bayes Theorem... Oh well...
Here is the question, and my solution (not at the interview though ;-))


We are given two drawers, one contains only black balls, the other one 50% black balls, and 50% white balls. I pick up a ball at random, it turns out that the ball is black, what is the probability that this black ball comes from the first drawer?


You must now remember the Bayes Theorem:


P(A|B) = P(B|A) * P(A) / P(B), where:

* P(A) is the prior probability of A
* P(A|B) is the conditional probability of A given B - or posterior probability
* P(B|A) is the conditional probability of B given A
* P(B) is the marginal probability of B


So, we can re-phrase the question like:


What is the probability that I picked up the first drawer (the one with only black balls), given that I picked up a black ball.


And we have:


* P(A) is the prior probability that I picked up drawer #1 without any other info, that is 1/2
* P(B) is the prior probability that I picked up a black ball without any other info, that is 3/4, because there are 1 black balls in #1, 0.5 black balls in #2, and 0.5 white balls in #2
* P(B|A) is the probability of getting a black ball given I chose drawer #1, because there are only black balls, it is 1

So we have P(A|B) = (1 * 1/2) / (3/4) = 2/3

So the answer is 2/3.


The good thing about this interview is that I will know the Bayes Theorem for the next one!

Safari on Windows

• Ugly


• Slow


• Crashed


• World Best Browser (Ahahahaha)

Glass-Steagall

Could this be the source of the financial meltdown we are witnessing?
Read the Demise of the Glass-Steagall act

Echo3

Echo3 is an impressive Open Source framework for AJAX dev... Check out the demo!

Prime Obsession

I would like to tell you about a great book I am reading, Prime Obsession from John Derbyshire.
I enjoy books on mathematics, especially the books on history of mathematics (The Last Fermat Theorem, ..).

This book is about the Riemann Hypothesis, an Derbyshire is doing a great job at introducing the concept to people with little knowledge of mathematics.

I studied in some Classes Preparatoires (well, “attended” would probably be the best word...), and I assure you that just an A-level is required to understand the book.

Reality Driven Development

I have been struggling to find a right name for my development methodology. RUP/UML does not work, XP results in punching your colleague, etc. etc.

I have always thought that the reality of the project (people, customers, bugs, change of plan, unseen issues, ...) would automatically lead to quick release-cycles, multiple demos, dozens of back-and-forth emails with the business...

So I adhere to the ideas of Gustavo Duarte on Reality Driven Development