Show HN: AI explanations for other people’s code
A pretty big warning and tell on the current state of "AI" : <a href="https://whatdoesthiscodedo.com/g/3a3ec39" rel="nofollow">https://whatdoesthiscodedo.com/g/3a3ec39</a><p>That is the famous fast inverse square root [1] from Quake, with a handful of completely inconsequential changes. I renamed the function from "Q_rsqrt" to "Floor", and I renamed one variable from "threehalfs" to "magicNumber". I also removed the various comments. The intent was to demonstrate the flaws in the current "guess the next word" style algorithm of large language models. The result:<p>-----<p>The code is an implementation of the floor function for floating-point numbers. The floor function returns the largest integer value that is less than or equal to a given input number.<p>The code works by first dividing the input number by 2 and storing the result in a variable called x2. It then stores the original input number in a variable called y.<p>Next, it performs some bit manipulation on the binary representation of y to obtain an approximation of its inverse square root. This is done using the following "magic number" constant: 0x5f3759df. The resulting value is stored in i.<p>The code then converts the binary representation of i back into a float value and multiplies it by a correction factor, which is based on the original input number and the inverse square root approximation. This correction factor is computed as follows:<p>magicNumber - (x2 * y * y)<p>Finally, the resulting value is returned from the function as the floor of the input number.<p>-----<p>[1] - <a href="https://en.wikipedia.org/wiki/Fast_inverse_square_root" rel="nofollow">https://en.wikipedia.org/wiki/Fast_inverse_square_root</a>