Om Malik’s Broadband Blog » Why Skype-eBay was the Worst Kept Secret On Wall Street
However, a post over on Skype forums says that the leak might have come from a cabbie in New York who overheard the eBay Executives. And you thought they didn’t understand english….
Donald Rumsfeld is giving the president his daily briefing.
He concludes by saying: “Yesterday, 3 Brazilian soldiers were killed in an accident”.
“Oh no!” the President exclaims. “That’s terrible” His staff sits stunned at
this display of emotion, nervously watching as the president sits, head in his
hands.
Finally, the President looks up and asks………. ‘’How many is a Brazillion??!”
I made a recent post about rational geometry, or a way to solve geometric problems with no need for trigonometric functions.
My intuition is that this new (apparently the Chinese invented it more than a thousand years ago) way of doing geometry can be very useful for machines.
I ran a very simple experiment. At the end of Chapter 1 from the referenced book, there is a simple geometric problem with the traditional solution and the rational solution.
I have implemented the solution in Java and run some measurements. The rational solution is x4 faster.
Note that the code requires Java 1.5, in order to access the new nanosecond timer.
The output is as follows:
java Geometry
3.313693059275397 computed in 200000ns
3.3136930592753853 computed in 23000ns
3.313693059275397 computed in 1046.7512ns
3.3136930592753853 computed in 250.1114ns
public class Geometry
{
public static void main(String args[])
{
long start, end;
int ITER = 5000000;
/* WARMING UP */
// traditional way
start = getTime();
double alpha = Math.acos( (float)3/4);
double beta = Math.PI - Math.PI/4 - alpha;
double d = 5 * Math.sin(alpha) / Math.sin(beta);
end = getTime();
System.out.println(d + " computed in " + (end-start) + "ns");
// rational geometry
start = getTime();
double q1 = 1400 - 525*Math.sqrt(7);
double d1 = Math.sqrt(q1);
end = getTime();
System.out.println(d1 + " computed in " + (end-start) + "ns");
/* WE ARE WARMED UP */
// traditional way
start = getTime();
for(int i=0; i
alpha = Math.acos( (float)3/4);
// System.out.println("alpha: " + alpha);
beta = Math.PI - Math.PI/4 - alpha;
// System.out.println("beta: " + beta);
d = 5 * Math.sin(alpha) / Math.sin(beta);
}
end = getTime();
System.out.println(d + " computed in " + (end-start)/(float)ITER + "ns");
// rational geometry
start = getTime();
for(int i=0; i
q1 = 1400 - 525*Math.sqrt(7);
d1 = Math.sqrt(q1);
}
end = getTime();
System.out.println(d1 + " computed in " + (end-start)/(float)ITER+ "ns");
}
public final static long getTime()
{
return System.nanoTime();
}
}
Virtual plague spreading like wildfire in World of Warcraft
This is one of the most interesting stories I have read.
It reminds me of a movie called The 13th Floor where a game goes beyond its purpose.
Le Monde.fr : Enseignement supérieur et recherche, l’heure des choix, par Nicolas Sarkozy
Article intéressant.
2 remarques :
Mon expérience en France (Ecole Polytechnique, Ponts et Chaussées, DEA à Jussieu) et aux USA (PhD à University of Pennsylvania à Philadelphie) m’a montré que la différence principale entre les deux mondes est la responsabilité ou responsabilisation. En France un enseignement qui vit de la manne de l’Etat. Aux USA, un enseignement qui se finance de lui même, parfois grâce à l’Etat (e.g. financement pour les projets de recherche).
Aux USA, l’enseignement est un business. Il est ouvert à tous, moyennant $$. En France, l’enseignement est un droit.
Lequel des deux systèmes est le plus juste ? Je suis au regret de constater que le système le plus juste est le système américain. En France, il est pratiquement impossible de poursuivre certaines études passé un certain âge.
Entre la discrimination par l’âge (en France) et celle par l’argent (aux USA), je préfère la seconde.
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