Introduction to Gradient Descent

April 24, 2012

In a previous post, I presented (generalized) linear regression from a linear algebra point of view (namely, the “normal equations”) and in this post, I discuss yet another take on the problem, this time using gradient descent.

Gradient descent isn’t particularly fascinating for this particular task (as we know closed, analytical expressions for obtaining the parameters), but linear regression is the simplest example of gradient descent I could come up with without being completely trivial.

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New Way of Computing Square Roots?

April 17, 2012

I sometimes have quite nerdy readings. As of late, I’ve been reading Le fabuleux destin de \sqrt{2} (The Fabulous Destiny of \sqrt{2}, one might translate) by Benoît Rittaud. This book is a treasure trove of \sqrt{2} facts, and one caught my eye more than the others so far: an iterative method to compute square roots of any (positive) number.

When the method is first presented, he leaves to the reader to find a demonstration (though he gives one much later on, several chapters later), but let’s see what we can find.

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Wallpaper: Je me souviens

April 15, 2012

(Je me souviens, 1920×1200)

In memory of the 1989 Polytechnique victims

Reblog if you’re in favor of saving the Canadian Firearm Registry.

Les Anciens

April 13, 2012

Contrairement à ce que croyaient les Anciens Grecs, le rôle de la science n’est pas de fignoler des représentations délectables, mais de prendre l’Univers comme elle le trouve.

Marcel Boll

Histoire des mathématiques

Herding Cats

April 10, 2012

I’m sure you’ve heard the expression herding cats before. When you’re trying to manage programmers, the expression certainly comes to mind. What if programmers were cats, which one would you be?

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