pc-COP: An Efficient and Configurable 2048-p-Bit Fully-Connected Probabilistic Computing Accelerator for Combinatorial Optimization

Abstract: Probabilistic computing is an emerging quantum-inspired computing paradigm capable of solving combinatorial optimization and various other classes of computationally hard problems. In this work, we present pc-COP, an efficient and configurable probabilistic computing hardware accelerator with 2048 fully connected probabilistic bits (p-bits) implemented on Xilinx UltraScale+ FPGA. We propose a pseudo-parallel p-bit update architecture with speculate-and-select logic which improves overall performance by $4 \times$ compared to the traditional sequential p-bit update. Using our FPGA-based accelerator, we demonstrate the standard G-Set graph maximum cut benchmarks with near-99% average accuracy. Compared to state-of-the-art hardware implementations, we achieve similar performance and accuracy with lower FPGA resource utilization.