# Tag Archives: Math

## 10 Awesome Theorems & Results

When I look back at various mathematical courses I took, most have at least one theorem that I really liked. Usually I like it because the proof has a surprising trick, sometimes it’s because of the unexpected conclusion, or maybe … Continue reading

Posted in Cryptography, Math | Tagged , | 13 Comments

## The mathematics behind the solution for Challenge No. 5

If you take a look at the various solutions people proposed for the last challenge of generating a specific permutation, you’ll see that they are very similar. Most of them are based on some form of div-mod usage. The reason … Continue reading

## Fast Peak Autocorrelation

So, I was at geekcon. It was a blast. There were many interesting projects, and I didn’t get to play with them all. I did get to work a bit on the Lunar Lander from last year, and this year … Continue reading

## Checking the ulam spiral

In the following post, the Ulam spiral is described. It’s a very simple object – write down consecutive natural numbers starting from 41 in a square spiral. Curiously, the numbers on the diagonal are primes: Reading this post, I immediately … Continue reading

Posted in Math, Programming, Python | | 4 Comments

## Fun with Matrices

I’ll let the code speak for itself: In [81]: m = Matrix(array([[1.0,1.0],[0.0,1.0]]))   In [82]: def my_sqrt(x, num_iters): ….: r = 0.5*x ….: for i in xrange(num_iters): ….: r = 0.5*(r+x/r) ….: return r ….:   In [83]: m*m Out[83]: … Continue reading