Accelerating Nuclear Configuration Interaction Calculations through a Preconditioned Block Iterative Eigensolver

TL;DR

This paper introduces a preconditioned block iterative eigensolver that significantly accelerates large-scale nuclear configuration interaction calculations on parallel supercomputers, outperforming traditional Lanczos methods.

Contribution

The paper presents a novel preconditioned block iterative eigensolver tailored for nuclear physics, improving convergence and computational efficiency over existing methods.

Findings

Achieves 2-3x speedup over Lanczos algorithm on supercomputers.

Effectively utilizes problem structure and memory hierarchy for performance gains.

Demonstrates scalability on high-performance parallel architectures.

Abstract

We describe a number of recently developed techniques for improving the performance of large-scale nuclear configuration interaction calculations on high performance parallel computers. We show the benefit of using a preconditioned block iterative method to replace the Lanczos algorithm that has traditionally been used to perform this type of computation. The rapid convergence of the block iterative method is achieved by a proper choice of starting guesses of the eigenvectors and the construction of an effective preconditioner. These acceleration techniques take advantage of special structure of the nuclear configuration interaction problem which we discuss in detail. The use of a block method also allows us to improve the concurrency of the computation, and take advantage of the memory hierarchy of modern microprocessors to increase the arithmetic intensity of the computation relative to data movement. We also discuss implementation details that are critical to achieving high performance on massively parallel multi-core supercomputers, and demonstrate that the new block iterative solver is two to three times faster than the Lanczos based algorithm for problems of moderate sizes on a Cray XC30 system.