# ElasTool: An automated toolkit for elastic constants calculation

## Description

We present the ElasTool package, an automated toolkit for calculating the second-order elastic constants (SOECs) of any two- (2D) and three-dimensional (3D) crystal systems. ElasTool uses three kinds of strain-matrix sets, i.e., the high-efficiency strain-matrix sets (OHESS), the universal linear-independent coupling strains (ULICS), and the all-single-element strain-matrix sets (ASESS), to calculate the SOECs automatically. ElasTool can efficiently compute both zero- and high-temperature elastic constants. We describe in detail the theoretical background and computational method of elastic constants, the package structure, the installation, and run, the input/output files, the controlling parameters, and two representative examples of how to use the ElasTool package. ElasTool is useful for either the exploration of materials' elastic properties or high-throughput new materials screening and design. ElasTool is freely available on GitHub: https://github.com/elastool