Exploitation of Parallel Search Space Evaluation with FPGAs in Combinatorial Problems: The Eternity II Case

The Eternity II puzzle is a combinatorial search problem which qualifies as a computational grand challenge. As no known closed form solution exists, its solution is based on exhaustive search, making it an excellent candidate for FPGA-based architectures, in which complex data structures and non-trivial recursion are implemented in hardware. This paper presents such an architecture, which was designed and fully implemented on a Virtex5 FPGA (XUP ML505 board). Despite the serial nature of the recursion, as parallelism can be applied with the initiation of multiple searches, the system shows a measured speedup of 2.6 vs. a high-end multi-core compute server.