From a020470347bbc4c0b188a64d4d832097d5741e50 Mon Sep 17 00:00:00 2001 From: YB_HU <138468445+RussellHu41@users.noreply.github.com> Date: Mon, 6 Jan 2025 15:37:20 +0800 Subject: [PATCH] Create ABACUS_31_12_2024.md (#212) --- source/_posts/ABACUS_31_12_2024.md | 58 ++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 source/_posts/ABACUS_31_12_2024.md diff --git a/source/_posts/ABACUS_31_12_2024.md b/source/_posts/ABACUS_31_12_2024.md new file mode 100644 index 0000000..22ce097 --- /dev/null +++ b/source/_posts/ABACUS_31_12_2024.md @@ -0,0 +1,58 @@ +--- +title: "ABACUS 3.9 Released | Significantly Improved Efficiency in Plane Wave Basis Set Calculations and New Constant Potential Simulation Function" +date: 2024-12-31 +categories: +- ABACUS +--- + +Atomic Abacus (ABACUS) is an open-source first-principles calculation software. It supports electronic structure calculations and molecular dynamics simulations based on density functional theory. ABACUS allows users to choose plane wave basis sets or numerical atomic orbital basis sets for functions such as electronic self-consistent iterations, band structure, density of states calculations, and structural optimizations. In addition, it supports multiple DFT theoretical methods including Kohn-Sham DFT, Real-time TDDFT, Stochastic DFT, Orbital-Free DFT. ABACUS supports various exchange-correlation functionals such as local density approximation (LDA), generalized gradient approximation (GGA), metaGGA, and hybrid functionals. ABACUS also provides good support for multiple AI-assisted algorithms such as DeePKS, DeePMD, DeePTB, and DeepH. The ABACUS development team aims to support high-precision, high-stability, multi-platform, and large-scale calculations. It conducts online collaborative development in an open-source mode and ensures the rapid iteration of ABACUS in terms of functionality, performance, and reliability by constructing a high-throughput and cross-platform automated test workflow. + + + +## Version 3.9 overview + +The ABACUS 3.9 version has focused on optimizing the efficiency issues of the plane wave basis set that have received more user feedback. The time-consuming part of the plane wave basis set solution mainly lies in the diagonalization process. The ABACUS team has significantly improved the computational efficiency of Davidson diagonalization by optimizing the implementation details of Davidson diagonalization. After optimization, the calculation time of ABACUS plane wave calculations on the CPU can be reduced by more than half, and the computational efficiency reaches the advanced level of international similar software. The plane wave calculation efficiency of the DCU version has also been improved by about 30%. In addition, the development team has developed and supported the contribution of spin-orbit coupling effects to atomic forces and lattice stresses in non-collinear magnetic calculations. Currently, the force and stress difference tests of non-collinear magnetic calculations including SOC can pass with high precision. The ABACUS team has also added a constant potential simulation function in the new version and prepared a ready-to-use tutorial, providing more tools for surface chemistry simulations. The new version has also optimized the problem of relaxation difficulties in some systems reported by users. Currently, a standard BFGS algorithm has been added, and the new BFGS has performed well in tests. + +## Version 3.9 introduction + +### Efficiency optimization of the Davidson iteration method under the PW basis set + +In ABACUS, the plane wave basis set (PW) uses an iterative method to solve the diagonalization of the Hamiltonian. Currently, two Davidson diagonalization solution methods are supported. According to whether the orthogonality is maintained in the Davidson subspace expansion algorithm, they are divided into the standard Davidson method (keyword: ks_solver dav) and the Davidson method with non-orthogonal subspace (keyword: ks_solver dav_subspace). In version 3.9, the computational efficiency of the dav_subspace method has been optimized. The computational efficiency on the CPU is nearly doubled compared to the traditional Davidson algorithm (keyword: ks_solver dav), and significant efficiency improvements can also be obtained on the GPU or Dawning DCU. Currently, when using the PW basis set of ABACUS for norm-conserving pseudopotential calculations, the recommended INPUT settings related to diagonalization are: ks_solver dav_subspace + pw_diag_ndim 2. + +
+ +### Calculation of atomic forces and lattice stresses under non-collinear spins + +Both noncollinear-spin and spin-orbit-coupling will automatically set nspin = 4. In the analytical calculation of atomic forces and lattice stresses, additional correction terms for the forces induced by non-collinear electron spins and spin-orbit coupling need to be considered. Version 3.9 supports the calculation functions of atomic forces (cal_force 1) and lattice stresses (cal_stress 1) for nspin = 4 using the PW basis set and LCAO basis set. The analytical calculation results can pass strict energy difference tests. + +### Constant potential method + +Microscopic-scale computational simulations of electrocatalytic systems are an indispensable research means for exploring relevant mechanisms. In experiments, the potential of the working electrode in an electrochemical surface reaction is controlled by an external circuit, and the potential remains constant during the reaction. However, the electrochemical open system composed of the electrode or catalyst material surface and the solution poses a high challenge to computational simulations. In traditional electronic structure theoretical methods, first-principles calculations based on density functional theory usually deal with the canonical ensemble, that is, computational simulations of electrochemical reactions are usually based on a constant number of electrons and are carried out under constant charge conditions. During the simulation process, the charge density of the material surface and the corresponding potential will change drastically. There is often a large difference in the potential between the initial and final states of the calculation, thus ignoring the influence of the potential on the reactivity in the experiment and making it difficult to accurately describe the basic properties of a charged system. Therefore, accurate modeling of the electrochemical interface is crucial for understanding electrochemistry and electrocatalysis on the electrode. This requires that the electrode potential (Fermi level) is fixed while the total number of electrons can vary at the atomic level. Professor Hai Xiao's research group at Tsinghua University has developed an efficient fully converged constant-potential (FCP) algorithm based on the Newton method [1], which can efficiently converge the simulation system to the preset electrochemical potential. We have implemented constant potential calculations using ABACUS as the first-principles calculator of this method based on the Python interface of ASE. + +### Standard BFGS method in structural relaxation + +ABACUS supports the optimization function of relaxing the atomic positions or lattice to find a stable structure (calculation relax/cell-relax). According to user feedback in the Issue, in some systems, the convergence efficiency of the BFGS (Broyden-Fletcher-Goldfarb-Shanno) algorithm already implemented in ABACUS is not high enough. However, using the standard BFGS algorithm in combination with ASE + ABACUS is more efficient in optimizing these systems. In version 3.9, a function for performing structural optimization calculations using the standard BFGS algorithm has been added (key parameter: relax_method bfgs_trad). Direct use of ABACUS for optimization is more convenient and will enable initial guess optimization functions such as charge density extrapolation to accelerate the convergence speed of SCF in the relax/cell-relax calculation process. + +### Conclusion + +User feedback is the most valuable driving force for ABACUS to continuously progress. During the development of version 3.9, the ABACUS development team has addressed several issues reported by users, such as low efficiency of the plane wave basis set, large errors in stress differences in non-collinear calculations, the need to support constant potential simulations, and difficulty in convergence of relaxation in some systems. The efficiency of plane wave calculations in the new version of ABACUS has been improved by more than 100%, and the Force and Stress in non-collinear calculations are accurate and reliable. In addition, it also supports constant potential simulations and a new BFGS relaxation algorithm. The ABACUS team plans to support and optimize more relaxation algorithms in the next version. The team will continue to uphold the spirit of open source and openness, strive to further improve the correctness, stability, and ease of use of ABACUS, and aim to benchmark against international mainstream density functional theory software in major functions and even surpass them in some special functions. The open-source code development team of ABACUS also hopes to continue to receive the support and help of users. + +## Quick access addresses + +ABACUS GitHub repository address in the DeepModeling community: +https://github.com/deepmodeling/abacus-develop + +ABACUS 3.9 version release notes: +https://github.com/deepmodeling/abacus-develop/releases/tag/v3.9.0 + +ABACUS online documentation (including installation methods, input and output parameter introductions, function introductions, example introductions, developer instructions, etc.): +https://abacus.deepmodeling.com/en/latest/ + +User and developer questions and discussions: +https://github.com/deepmodeling/abacus-develop/issues +https://github.com/deepmodeling/abacus-develop/discussions + +## References + +[1] Xia, Z. & Xiao, H. Grand Canonical Ensemble Modeling of Electrochemical Interfaces Made Simple. Journal of Chemical Theory and Computation (2023) +doi:10.1021/acs.jctc.3c00237.