IFS numerical weather prediction system
The European Centre for Medium-Range Weather Forecasts (ECMWF) runs its operational weather forecasting workflow four times each day. This workflow, containing ECMWF’s Integrated Forecast System (IFS), runs an ensemble of 51 weather forecasts and a single ‘high-resolution’ forecast that predict the weather for up to 15 days. Data generated by the forecast model is then post-processed by a swarm of workflow components to generate and disseminate products to ECMWF’s Member and Co-operating States and other licensed customers. The enormous data exchanges required between workflow components create a bottleneck, potentially restricting future increases in forecast resolution.
Maestro is expected to orchestrate more efficient data movement between the workflow components. This will also help ECMWF to exploit novel storage technologies and heterogeneous storage architectures, and to improve its management of data dependencies. These changes will help to accelerate the processing and delivery of higher resolution data to its users.
Computational Fluid Dynamics plus in-situ analysis
This application is a simplified setup of a realistic usage scenario where multiple simulation codes are chained and combined with data analysis and visualisation pipelines. Chaining of simulation codes is often used to model different physics and/or scales, with the output of the first code being used as the input of the second with an intermediate data transformation or preparation step and a final post-processing step. For this simplified setup the open source proxy application Hydro is used, a 2D hydrodynamic simulation code, to perform simulations at different scales. Two post-processing pipelines are then run using the simulation output data: A custom data analysis pipeline written in Python and a visualisation pipeline using ParaView and FFmpeg to produce a movie of the simulation.
Global Earth System Modelling system TerrSysMP
Global Earth System Modelling faces the challenge of having to couple different models. The Terrestrial Systems Modelling Platform (TerrSysMP) targets the simulation of interactions between lateral flow processes in river basins and lower atmospheric layers. This is achieved by combining three model components COSMO, CLM and ParFlow. COSMO models the atmosphere, the Community Land Model (CLM) is used to study the effect of terrestrial ecosystems on climate, and Paraflow provides hydrological models to simulate surface and subsurface flow. TerrSysMP is used to co-design Maestro such that it can be used for coupling these different models.
Electronic structure calculation library SIRIUS
The Density Functional Theory (DFT) is an established approach for computing electronic structures of materials. SIRIUS is a domain specific library to realise DFT applications. It includes compute-intensive kernels that are good candidates for being accelerated on GPUs. On servers comprising CPUs and GPUs this requires data to be placed in the memory attached to CPUs and GPUs and to be exchanged between both types of memory. In the case of SIRIUS this can become challenging as the matrices involved in the calculation are usually large and therefore do not always fit into the memory of the GPU. Maestro is used to support chunking of the data and the transfer of these chunks to the GPU.
Montage is an application developed to assemble astronomical images of the sky into a mosaic. Depending on the number of images, it can result in a complex workflow comprising various tasks that can process data independently. To manage such a complex set of tasks workflow managers are being used, which in this case is Pegasus. Montage is used to co-design workflow support of the Maestro middleware and Maestro workflow tools.