Convergence verification of the Collatz problem

This software contains computer programs implementing a completely new approach to calculating iterates of the Collatz function. The trick is that, when calculating the function iterates, the programs switch between two domains in such a way that they can always use the count trailing zeros (ctz) operation and a small lookup table with pre-computed powers of three. This approach differs significantly from the commonly used approach utilizing a space-time tradeoff using huge lookup tables. The programs can check 128-bit numbers.