EDIpack: A parallel exact diagonalization package for quantum impurity problems

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 Ref. [1] 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. Program summaryProgram title: EDIpackCPC Library link to program files:https://doi.org/10.17632/2hxhw9zjg9.1Code Ocean capsule:https://codeocean.com/capsule/3537659Licensing provisions: GPLv3Programming language: Fortran, PythonExternal dependencies: CMake (>=3.0.0), Scifortran, MPINature of problem: The solution of multi-orbital quantum impurity systems at zero or low temperatures, including the effective description of lattice models of strongly correlated electrons, are difficult to determine.Solution method: Use parallel exact diagonalization algorithm to compute the low lying spectrum and evaluate dynamical correlation functions.