  We here 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. It can utilize three kinds of
strain-matrix sets, 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. In an automatic manner, ElasTool can deal with both zero- and
high-temperature elastic constants. 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 ElasTool are described detailedly. ElasTool is
useful for either the exploration of materials' elastic properties or
high-throughput new materials design. ElasTool is also available at our
website: www.matdesign.cn.
