This module implements the first version of the DL_MESO_DPD Mesoscale Simulation Package, with multiple NVidia Graphical Processing Units (GPUs).

In this module the main framework of a multi-GPU version of the DL_MESO_DPD code has been developed. The exchange of data between GPUs overlaps with the computation of the forces for the internal cells of each partition (a domain decomposition approach based on the MPI parallel version of DL_MESO_DPD has been followed). The current implementation is a proof of concept and relies on slow transfers of data from the GPU to the host and vice-versa. Faster implementations will be explored in future modules.

Future plans include benchmarking of the code with different data transfer implementations other than the current (trivial) GPU-host-GPU transfer mechanism. These are: of Peer To Peer communication within a node, CUDA-aware MPI, and CUDA-aware MPI with Direct Remote Memory Access (DRMA).

Practical application and exploitation of the code

Dissipative Particle Dynamics (DPD) is routinely used in an industrial context to find out the static and dynamic behaviour of soft-matter systems. Examples include colloidal dispersions, emulsions and other amphiphilic systems, polymer solutions, etc. Such materials are being produced or processed in industries like cosmetics, food, pharmaceutics, biomedicine, etc. Porting the method to GPUs is thus inherently useful in order to provide cheaper calculations.

See more information in the industry success story recently reported by E-CAM.

Software documentation and link to the source code can be found in our E-CAM software Library here.

Here present two featured software modules of the month:

1. ParaDiS with precipitates
2. ParaDiS with precipitates optimized to HPC environment

that provide extensions to the ParaDIS Discrete dislocation dynamics (DDD) code (LLNL, http://paradis.stanford.edu/) where dislocation/precipitate interactions are included. Module 2 was built to run the code on an HPC environment, by optimizing the original code for the Cray XC40 cluster at CSC in Finland. Software was developed by E-CAM partners at CSC and Aalto University (Finland).

Practical application and exploitation of the codes

The ParaDiS code is a free large scale dislocation dynamics (DD) simulation code to study the fundamental mechanisms of plasticity. However, DDD simulations don’t always take into account scenarios of impurities interacting with the dislocations and their motion. The consequences of the impurities are multiple: the yield stress is changed, and in general the plastic deformation process is greatly affected. Simulating these by DDD allows to look at a large number of issues from materials design to controlling the yield stress and may be done in a multiscale manner by computing the dislocation-precipitate interactions from microscopic simulations or by coarse-graining the DDD results for the stress-strain curves on the mesoscopic scale to more macroscopic Finite Element Method.

Modules 1 and 2 provide therefore an extension of the ParaDIS code by including dislocation/precipitate interactions. The possibility to run the code on HPC environments is also provided.

Software documentation and link to the source code can be found in our E-CAM software Library here.