asi4py 1.4.1

A Python wrapper for Atomic Simulation Interface API

Atomic Similation Interface (ASI) API

Atomic Simulation Interface (ASI) is a native C-style API that includes functions for export and import of data structures that are used in electronic structure calculations and for classical molecular dynamics simulations. ASI aims to be a uniform, generic and efficient interface for connecting various computational chemistry and materials science codes in multiscale simulation workflows, such as QM/MM, QM/ML, QM/QM. ASI specifies functions, data types and calling conventions for export and import of density matrices, overlap and Hamiltonian matrices, electrostatic potential, atomic coordinates, charges, total energy and forces.

ASI API specification

ASI API is specified as a C header file asi.h. Codes implementing ASI API must provide linkable library with definitions of functions from asi.h. Depending on particular usage of the implementaions, some functions can be ommited or implemented as stubs, if they are not going to used. To use Python ASI wrapper it is necessary to have all functions from asi.h defined, but of course stub definitions can be used.

ASI API specification.

Supported in:

• DFTB+: in separate branch.
• FHI-aims: in the main branch.

Building

FHI-aims

FHI-aims has embedded support of ASI API. Just build latest version of FHI-aims as a shared library and use with your code.

DFTB+

1. Download and build DFTB+ from the branch with ASI API with shared library support.

2. Set environment variables DFTBP_INCLUDE and DFTBP_LIB_DIR to folders with DFTB+ C-headers and libraries.

3. Optionally export environment variables INSTALL_PREFIX and BUILD_PATH to set installation and building locations.

4. Run make && make install from the root of the working copy of this repository.

5. The shared library implementing ASI API for DFTB+ will be in ${INSTALL_PREFIX}/lib.

Testing

Use Makefile in tests folder to build native tests. Set environment variables in the header of tests/Makefile to link with proper ASI API implementaions.

To run tests go to tests/testcases and run run_dftbp_tests.sh or run_aims_tests.sh to run test.

Usage

See tests/src for examples of usage in native code.

See tests/python for examples of usage in Python scripts.