Thanks wenchiet for this Nokia phone shooting.

# Author: zkchong

## A Talk of Robust Solution

I am not the expert in vehicle routing. But, I do learn a lesson from Prof. Sam Thangiah’s talk in FICT UTAR today.

The rough meaning is something like this:

*Best solution appears in publication. But in real world, only the robust solution does matter.*

For example, Dijkstra’s algorithm works perfectly in finding the shortest path from point A to point B. However, it seems not to be feasible when it is applied to calculating the pick-up points for buses in a city. Heuristic approach is much appreciated instead.

## Registration of Marriage, 2009

## The Only Simple Reason.

## Leisure Reading – Gantz

*A pair of high school students, Kei Kurono and Masaru Kato, are run over by a subway train in an attempt to save the life of a homeless drunk who had fallen onto the tracks. Following their deaths, Kurono and Kato find themselves transported to the interior of an unfurnished Tokyo apartment. And, a sphere that are known as “Gantz”, commanded them to kill an alien somewhere in Tokyo … (Quoted from http://en.wikipedia.org/wiki/Gantz).*

*I like this manga as they have a fine drawing and the nice storyline. But, RM44 per book is not cheap!
*

## Tackling Polynomial Equations with Python (Numpy)

How to calculate a polynomial of (s+1)(s+2)…(s+10) in a short time?

Instead of calculate them one by one, we can do it with the help of Python library – Numpy.

1. Make sure you have installed Numpy for your Python interpreter. In Ubuntu, you may just want to install *python-scipy* as it contains all the scientific calculation tools.

2. Try the following example in your python interpreter:

from numpy import * p1 = poly1d(1, 1 ) #(S+1) p2 = poly1d(1, 2 ) #(S+2) p3 = poly1d(1, 3 ) #(S+3) p4 = poly1d(1, 4 ) #(S+4) p5 = poly1d(1, 5 ) #(S+5) p6 = poly1d(1, 6 ) #(S+6) p7 = poly1d(1, 7 ) #(S+7) p8 = poly1d(1, 8 ) #(S+8) p9 = poly1d(1, 9 ) #(S+9) p10 = poly1d(1, 10) #(S+10) print p1*p2*p3*p4*p5*p6*p7*p8*p9*p10

3. Then, you will an get an output like:

10 9 8 7 6 5 4 3 2 1 x - 10 x + 45 x - 120 x + 210 x - 252 x + 210 x - 120 x + 45 x - 10 x + 1

That is the answer:

x^10 - 10x^9 +45x^8 - 120x^7 + 210x^6 - 252x^5 + 210x^4 - 120x^3 + 45x^2 - 10x + 1

4. Say, we need to find the root of this polynomial. With the help of Python, we can get the roots by feeding these line into the interpreter.

(p1*p2*p3*p4*p5*p6*p7*p8*p9*p10).r #.r means root.

And, we will get an output like this:

array([ 1.04405137+0.0143565j , 1.04405137-0.0143565j , 1.02709855+0.03755416j, 1.02709855-0.03755416j, 0.99974141+0.04619473j, 0.99974141-0.04619473j, 0.97275208+0.03706564j, 0.97275208-0.03706564j, 0.95635659+0.01406697j, 0.95635659-0.01406697j])

The polynomial has 5 complex conjugates: *1.04405137 +/- 0.0143565j, 1.02709855 +/- 0.03755416j, 0.99974141+/- 0.04619473j, 0.97275208 +/-0.03706564j, 0.97275208 +/- 0.03706564j and 0.95635659 +/- 0.01406697j *.

## [J-Drama] With Love

<With Love> is the first Japanese drama that I watched in my secondary school. Seeing this youtube brings me back to my sentimental high school puppy love. @_+

The storyline goes as follows:

*Takashi (Takenouchi), a talented composer, who could not write a love song ever since his girlfriend Rina left him suddenly. Accidentally, Takashi sent an uncompleted piece of his latest work to Amane (Tanaka) via email. *

*Deeply touched by his music, Amane wrote back to him, without getting a reply. Amane continued writing to him, pouring out her thoughts, with the nickname of “Teru Teru Bozu”. One day, Takashi responded with a mail saying “WHO ARE YOU?” because what Rina left him as a farewell gift was a teru teru bozu! *

(Quoted from http://jdorama.com/drama.445.htm)