Hey Ashton, when GenStage was first released I wanted to make something practical with it in Elixir and ended up writing my own job manager. Then later I found a use case for this code which was sitting on the shelf. Felt pretty sweet.

This sounds great. This will help a lot of junior developers like myself.

I’ve always admired the fast inverse square root function from Quake III Arena:

float q_rsqrt(float number)
{
  long i;
  float x2, y;
  const float threehalfs = 1.5F;

  x2 = number * 0.5F;
  y  = number;
  i  = * ( long * ) &y;                       // evil floating point bit level hacking
  i  = 0x5f3759df - ( i >> 1 );               // what the fuck?
  y  = * ( float * ) &i;
  y  = y * ( threehalfs - ( x2 * y * y ) );   // 1st iteration
  // y  = y * ( threehalfs - ( x2 * y * y ) );   // 2nd iteration, this can be removed

  return y;
}

This functions is called millions of times in that game, because you need to do inverse square roots to do graphics.

There’s a good write up on it’s history and meaning on Wikipedia.