EDIpack: A parallel exact diagonalization package for quantum impurity problems

TL;DR

EDIpack is a parallelized exact diagonalization software designed for quantum impurity problems, optimizing matrix operations and communication to handle large, complex systems efficiently.

Contribution

The paper introduces a novel parallel algorithm for exact diagonalization tailored to quantum impurity problems, improving scalability and handling multiple orbitals and electron-phonon interactions.

Findings

Achieves sub-linear scaling in large systems

Optimizes inter-process communication through Fock basis organization

Enables efficient parallel execution of Lanczos and Arnoldi algorithms

Abstract

We present EDIpack, an exact diagonalization package to solve generic quantum impurity problems. The algorithm includes a generalization of the look-up method introduced in [Lin, Gubernatis Comput. Phys., 7 (4) (1993), 400] and enables a massively parallel execution of the matrix-vector linear operations required by Lanczos and Arnoldi algorithms. We show that a suitable Fock basis organization is crucial to optimize the inter-processors communication in a distributed memory setup and to reach sub-linear scaling in sufficiently large systems. We discuss the algorithm in details indicating how to deal with multiple orbitals and electron-phonon coupling. Finally, we outline the download, installation and functioning of the package.