Flood Modeller-TUFLOW Benchmarking: Difference between revisions

The benchmark models in these tests are 2D only models or 1D-2D models which utilise TUFLOW 1D ESTRY engine. The speed up is due to 2D calculations being distributed across multiple processors and undertaken in parallel. The impact of the parallel processing is also seen in integrated 1D-2D models. As well as itsparallelisation own 1D engine which allowsof the modelling2D andcalculations, integrationimprovements ofhave pipealso networkbeen modelsmade andto riverthe modelsindexing together with aof 1D-2D domain,links TUFLOWthat can alsosubstantially bereduce integratedsimulation withtimes afor rangelarge oflinked other 11D-Dimensional2D software including <u>[https://www.floodmodeller.com/ Flood Modeller Pro]</u> amongst othersmodels.

A common query is what is the speed up of running simulations utilising TUFLOW HPC and GPU technology when TUFLOW models are linked to external 1D schemes such as Flood Modeller Pro. Therefore, some benchmarking runs of linked Flood Modeller Pro-TUFLOW models havehas been undertaken to demonstrate the show the impact of running the linked models with the TUFLOW HPC solver on a single processor, multiple cores as well as utilising Nvidia GPU cards. The outputs from these tests have been compared against the TUFLOW Classic engine which due to the various inter-dependencies in the matrix solver cannot efficiently distribute calculations across multiple processors.

The benchmark simulations have been undertaken internally and unfortunately due to model ownership and licensing issues cannot be supplied externally. However, if you would like to test your own Flood Modeller Pro-TUFLOW models on TUFLOW HPC GPU, we would be happy to run them on our machines to demonstrate the potential speed up. The models are real world example models typical of the kind that Flood Modeller Pro and TUFLOW are used on.

The results of the benchmarking of model 1 are shown in Table 1. The implicit TUFLOW Classic scheme is comparable to the TUFLOW HPC when itHPC is run on a couple of cores. This is due to the smaller timestep used in the explicit finite volume scheme which uses an adaptive timestep. As the number of cores used increases, the linked Flood Modeller Pro-TUFLOW HPC simulation is quicker, with run times reduced by up to 42%. A GPU card has a significant number of cores within it which can be utilizedutilised to undertake the 2D calculations. Running the same model on a GPU card leads to up to an 88% reduction in run times compared to TUFLOW Classic (and up to 84% compared to TUFLOW HPC without utilising a GPU Card). This means that nearly 8 simulations can be run on a GPU card in the same time that a single simulation could be run using TUFLOW Classic, highlighting the efficiencies of investing in hardware and also GPU modules. .

The second model contains 228 Flood Modeller Pro nodes, a 5m resolution TUFLOW grid with a total of 570,214 cells. The model was run for 26 hours of model time with a 100 year boundary condition. The TUFLOW Classic model was run with a 1.25 second timestep. Table 2 shows the run times for model 2 when run with the same scenarios areas model 1. The table shows that model run times can be up to 82% quicker when run on a GPU compared to TUFLOW Classic. Even when comparing the TUFLOW HPC GPU run time with the TUFLOW HPC run time when run utilising 8 cores, the simulation can be up to 74% quicker.

The results from the benchmarking of the hydraulic runs clearly show the impact of running models on TUFLOW HPC compared to TUFLOW Classic, and in particular the significance of running TUFLOW HPC on a GPU to significantly reduce model run times. The results show that linked Flood Modeller Pro-TUFLOW HPC run times are up to 8 times faster than TUFLOW Classic and up to 6 times faster than TUFLOW HPC when run on 8 CPU. Reducing model run times allows more efficiency by reducing the time taken to wait for simulations when various schematisation options are tested during the model build phase, increase productivity when running through the final design runs over a suite of return periods and durations, reducing licensing costs, and open up opportunities in terms of uncertainty analysis through Monte-Carlo type approaches which require a large ensemble of simulations to be conducted.

The simulation times were whenfor running the models using the latest release of Flood Modeller Pro 4.4. Flood Modeller Pro 4.4 although supporting TUFLOW HPC and GPU cards does not support the concurrent simulation of Flood Modeller Pro, TUFLOW HPC and TUFLOW’s 1D scheme, ESTRY. The ability to run all three simultaneously linked together is scheduled to be available in the Flood Modeller Pro 4.5 release which has been provided in a beta testing phase for this analysis. The ability to run Flood Modeller Pro, TUFLOW 2D and TUFLOW 1D components allows the running of a fully integrated drainage models comprising open channels, 2D floodplains as well as 1-Dimensional pipe networks and their interaction with the surface as represented by the 2D domain. The benchmarking of these types of models is currently being undertaken.