Loop Algorithm

Miriam Frankel

Ma, Kexiang, Zhang +1 more

Abstract:A low-delay loop detection algorithm for bit-flipping based iteration LDPC decoding is proposed.By introducing the concept of loop characteristic,only the iteration steps with loop characteristics are detected and labeled for the subsequent loop detection.As a result,computation delay is greatly reduced.Furthermore,the position vector for the selected iteration steps is also established to implement loop detection for these iteration steps,which reduces the hardware cost of the loop detection as well.The validity of the proposed algorithm is verified by simulations.

Filip Wojcieszyn

Ying-Jer Kao, Roger G. Melko

We present an algorithmic framework for a variant of the quantum Monte Carlo operator-loop algorithm, where nonlocal cluster updates are constructed in a way that makes each individual loop smaller. The algorithm is designed to increase simulation efficiency in cases where conventional loops become very large, do not close altogether, or otherwise behave poorly. We demonstrate and characterize some aspects of the short loop on a square lattice spin-1/2 XXZ model where, remarkably, a significant increase in simulation efficiency is observed in some parameter regimes. The simplicity of the model provides a prototype for the use of short loops on more complicated quantum systems.

Youjin Deng, Timothy M. Garoni, Wenan Guo +2 more

We develop cluster algorithms for a broad class of loop models on two-dimensional lattices, including several standard O(n) loop models at n> or =1. We show that our algorithm has little or no critical slowing-down when 1< or =n< or =2. We use this algorithm to investigate the honeycomb-lattice O(n) loop model, for which we determine several new critical exponents, and a square-lattice O(n) loop model, for which we obtain new information on the phase diagram.

Richard J. Lipton, Kenneth W. Regan