New Features Available to HPC
TUFLOW HPC’s solution scheme underwent extensive advanced development for the 2017 release. It now includes the majority of TUFLOW Classic features.
- The spatial accuracy was upgraded from 1st to 2nd order.
- It’s cell design was upgraded from a cell centered configuration, to a cell centre and face design. This is the same configuration as TUFLOW Classic. TUFLOW HPC now treats all thin and thick breakline topography modification inputs identical to TUFLOW Classic.
- TUFLOW HPC is linked with TUFLOW’s 1D solver, ESTRY. It has the same advanced 2D/1D link functionality as TUFLOW Classic.
- TUFLOW HPC now supports all 1D and most 2D boundary condition types, including:
- 1D and 2D QT, HQ and HT boundaries
- 2D SA and RF boundaries
- 1D/2D HX and SX boundaries
In addition to the above mentioned TUFLOW Classic inclusions, TUFLOW HPC includes a handful of new features that are specific to it, and not applicable to TUFLOW Classic:
CPU and GPU Execution Option
Modellers can now specify whether they would like to run TUFLOW HPC models on CPU or GPU hardware, with the ability to run the model across several CPU cores or GPU cards for increased modelling speeds. CPU simulations can be done using a standard TUFLOW licence. The GPU Hardware Module is required in addition to a standard TUFLOW licence to run on GPU.
Solution Scheme == HPC !Used to call the HPC solver. Classic is the default.
Hardware == CPU or GPU !The hardware command instructs TUFLOW to run the HPC model on either a CPU or GPU processor.CPU is default.
CPU Threads == 8 !This instructs TUFLOW to search for and run the model across four different core processors we run using CPU Hardware (i.e. This command does not apply to GPU). Default is 4.
GPU Device IDs == 0, 1 !This command instructs TUFLOW to run the model on GPU Device 0 and GPU Device 1.
TUFLOW HPC implements an adaptive timestep, meaning it changes over time, to meet the conditions of the model “Control Numbers” (see HPC Adaptive Timestepping). Using the "Control Number Factor ==" command, modellers can increase or decrease the HPC timestep.
The model timestep can be reduced (underclocked) by applying a Control Number Factor less than 1, or increased (overclocked) by implementing a Control Number Factor greater than 1. Reducing the model timestep is likely to increase model stability and model run times, while increasing the model timestep is likely to decrease model stability and run times.
Modellers can also define a minimum model timestep using the "Timestep Minimum == " command or a fixed model timestep with the "Control Number Factor == 0" command.
dt Map Output
The dt map output (see HPC Output Files) provides a raster grid of the minimum timestep in each cell of the model. To produce the dt raster grid, the following command is required in the TCF file.
"Map Output Data Type == dt"
Features not yet supported in HPC
Now TUFLOW HPC includes most TUFLOW Classic features it is easier to list the Classic features not yet included in HPC, instead of providing a full list outlining what HPC includes. The features below are currently not supported by TUFLOW HPC, though will be migrated across with time.
Bed Resistance coefficients
The Chezy and Fric bed resistance coefficients are not supported by HPC. Manning’s n is the only bed resistance coefficient currently supported by HPC.
Map Outputs Data Types
Map output data types not currently supported in HPC include:
- UD (User Defined Output)
- MB1 and MB2 (HPC is mass conserving and does not require these outputs)
- RC (Route Categories)
- n (Manning’s n values when using depth varying n values)
- R (flow regime)
- AP and WI (Atmospheric Pressure and Wind)
Minimum Map Outputs
Minimum value map outputs are not yet available in HPC.
Read GIS Z Shape Route
Evacuation route modelling (“Read GIS Z Shape Route ==”) is not yet supported in HPC.
Read GIS Objects
The “Read GIS Objects” feature which is used to record the water level and simulation time when one or more receptors are triggered in the model is not available in the HPC solver.
Reporting Locations, Longitudinal Profiles and Structure Groups
Reporting Locations, Longitudinal Profiles and Structure Groups are not yet fully built into HPC. These features are targeted for the next major HPC update.
Tracking of Plot Output Minimums and Maximums
HPC now tracks the minimum and maximum values for the plot outputs at each time series output interval. This still differs to Classic which is able to track the minimum and maximum values at every timestep of the model. Therefore there may be differences in the reported minimum and maximum values of these two TUFLOW engines. The degree of difference may be dependent on the time series output interval of the HPC model.
Traditional Flow Constrictions
2d_fc layers are currently not supported by HPC. If running a model with a traditional 2d_fc layer, HPC should report Error 2320.
Please note that layered flow constrictions (2d_lfcsh) are supported in HPC.
Water Level (_H) outputs for PO lines
HPC does not currently handle the _H (water level) output flag for the Plot Output feature. However, Plot Output points can still be used to produce a water level time series for a specified location.
Weir Factors (WrF) which are used for adjusting and calibrating 2d weir flow are not yet available in the HPC engine.
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