TeraChem protocol buffers (TCPB): Accelerating QM and QM/MM simulations with a client-server model

Area of Science:

• Computational Chemistry
• Molecular Modeling
• Quantum Chemistry

Background:

• Efficient access to electronic structure programs is crucial for chemical simulations.
• Graphics Processing Unit (GPU) acceleration offers significant speedups in computational chemistry.
• Integrating electronic structure calculations with other simulation packages can be challenging.

Purpose of the Study:

• To develop an efficient and user-friendly interface for accessing the GPU-accelerated TeraChem program.
• To enable seamless integration of TeraChem with third-party simulation software.
• To demonstrate the performance benefits and practical applications of the new interface.

Main Methods:

• Implemented TeraChem as an electronic structure server using Google's protocol buffer framework.
• Developed the TeraChem Protocol Buffers (TCPB) client interface for C++, Fortran, and Python.
• Integrated TCPB into the Amber software for Quantum Mechanics/Molecular Mechanics (QM/MM) simulations.
• Utilized Hamiltonian replica exchange for enhanced sampling in free energy profile calculations.

Main Results:

• TCPB significantly reduces GPU initialization and I/O times, achieving over 2x speedup.
• Demonstrated successful coupling of TeraChem with Amber for QM/MM simulations.
• Successfully computed the free energy profile of a model chromophore (p-HBDI-) in its excited state.

Conclusions:

• TCPB provides an efficient and accessible method for utilizing GPU-accelerated electronic structure calculations.
• The interface simplifies the integration of advanced computational chemistry tools into existing workflows.
• This approach facilitates complex simulations, such as QM/MM and free energy calculations, with improved performance.