Quantum dynamics of molecular systems in the GPU

Alberto Torres, Diego A. Hoff, Luis G. C. Rego

In this work we describe the use of Graphics Process Units (GPU) for numerical simulation of quantum dynamics of electronic states in molecular systems with the code DynEMol (Dynamics of Electrons in Molecules). Two time propagation methods have been carried out within the GPUs. In one case the quantum dynamics is propagated on a basis set of adiabatic orbitals which are gained from the diagonalization of a time-dependent hamiltonian by the MAGMA library (Matrix Algebra on GPU and Multicore Architectures). On the second case the quantum dynamics is evaluated on the diabatic basis comprised by the atomic orbitals by expanding the time propagator in the Chebyshev
polynomials. A CUDA routine has been developed to perform these calculations 100% within the GPU. In general, there is a considerable speed-up with the use of the GPU for large molecular systems (bigger than 10K orbitals), but the difference decreases with the size of the system. We present an efficiency evaluation for quantum dynamics calculations on single and multi-core CPU in regard to the GPU.