This repository 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. Mathematical details on this approach are given here. The programs can check 128-bit numbers.
David Barina ibarina@fit.vutbr.cz
This project is licensed under the terms of the MIT license.
- Barina, D. Convergence verification of the Collatz problem. J Supercomput 77, 2681–2688 (2021). https://doi.org/10.1007/s11227-020-03368-x
- Barina, D. Improved verification limit for the convergence of the Collatz conjecture. J Supercomput 81, 810 (2025). https://doi.org/10.1007/s11227-025-07337-0