Quantum ESPRESSO is an open-source distribution of computer codes for quantum-mechanical materials modeling, based on density-functional theory, pseudopotentials, and plane waves, and renowned for its performance on a wide range of hardware architectures, from laptops to massively parallel computers, as well as for the breadth of its applications. In this paper, we present a motivation and brief review of the ongoing effort to port Quantum ESPRESSO onto heterogeneous architectures based on hardware accelerators, which will overcome the energy constraints that are currently hindering the way toward exascale computing.
At the time, PWscf had already been released under the GPL.
Optionally, cuRAND can also be used for the generation of random wavefunctions.
Although as a rule the code should be executed with one MPI per GPU card, over-subscription of the GPU can lead to significant speedups, especially for small test cases. Nonetheless, over-subscription by more than a factor of 4 is seldom useful.
This can be appreciated by comparing simulations that required similar computational time on the CPU but used different pseudopotential sets, for example, the O10P2Ti and CaN2Si columns on the right panel of Fig. 2.