A new parallel simulation technique

TL;DR

The paper introduces a semi-parallel simulation method that divides spacetime into independent 4-volumes, enabling larger simulations without MPI and reducing processor idle time, demonstrated with cosmic string simulations.

Contribution

A novel semi-parallel simulation technique that improves efficiency and scalability over traditional MPI-based methods for large-scale spacetime simulations.

Findings

2.6 times reduction in processor time for cosmic string simulations

Enables larger simulations without memory limitations

No need for MPI communication between simulation segments

Abstract

We develop a "semi-parallel" simulation technique suggested by Pretorius and Lehner, in which the simulation spacetime volume is divided into a large number of small 4-volumes which have only initial and final surfaces. Thus there is no two-way communication between processors, and the 4-volumes can be simulated independently without the use of MPI. This technique allows us to simulate much larger volumes than we otherwise could, because we are not limited by total memory size. No processor time is lost waiting for other processors. We compare a cosmic string simulation we developed using the semi-parallel technique with our previous MPI-based code for several test cases and find a factor of 2.6 improvement in the total amount of processor time required to accomplish the same job for strings evolving in the matter-dominated era.