lbm2d_opencl
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LKedward
D2Q9 BGK Lattice Boltzmann code written in OpenCL and Modern Fortran.
D2Q9 BGK Lattice Boltzmann code written in OpenCL and Modern Fortran.
An OpenCL demonstration code making use of the Focal OpenCL abstraction library for Fortran.
Getting started
Prerequisites
- A modern fortran compiler supporting the 2008 standard (tested with gfortran 9.1.0)
- An openCL development library (One of: Intel OpenCL SDK, NVIDIA CUDA Toolkit, AMD OpenCL SDK )
Download
This project makes use of git submodules to bundle a library dependency.
Therefore to clone the repository:
$> git clone [email protected]:LKedward/lbm2d_opencl.git
$> git submodule init
$> git submodule update
Build
To compile, navigate to the repository directory and run make:
$> make -j
Parallel build is fully supported so use of the -j flag is recommended.
This will place executables in the ./bin/ directory.
To build the debug version:
$> make -j BUILD=debug
If the linker is unable to locate -lOpenCL you may have to specify the location of the OpenCL library (libOpenCL.so):
$> make -j OPENCL_DIR=/path/to/OpenCL/lib/
This should not be necessary on Linux platforms if the OpenCL development library is installed correctly
Run
To run the compiled program:
$> ./bin/lbmocl
Configuration file
When called with no arguments, the lbmocl program will run with a default configuration.
To specify alternative configuration options, specify a configuration file as the first argument, e.g.:
$> ./bin/lbmocl lbm.cfg
The following optional parameters may be specified in the configuration file:
CASE: (string) which built-in test case to run. Must be one of: CAVITY, CYLINDER, STEP. Default: CAVITY.
NI: (integer) number of lattice points in vertical direction. Default: 400.
N_ITER: (integer) number of unsteady timestep iterations to perform. Default: 5000.
SAVE_FREQ: (integer) how often to calculate macroscopic variables and save to disk. Default: 100 (every 100 timesteps).
SAVE_FILE: (string) filename of tecplot output. Default: lbm.plt.
SAVE_TYPE: (string) tecplot save mode. Must be one of: BIN, TXT for binary (fast,small) and ascii (portable) modes respectively. Default: BIN (recommended).
CL_VENDOR: (string) which hardware vendor to select device. Default: NVIDIA.
The following options override parameters defined by the built-in test cases:
DX: (float) overrides test case lattice grid spacing.
DT: (float) overrides test case time step.
TAU: (float) overrides test case relaxation parameter.
About the code
Files and directories
./src/lbmocl.f90: main program code./src/kernels.cl: OpenCL C kernel code implementing the lattice Boltzmann method./src/UserInput.f90: module for processing user inputs from configuration file./src/TecplotOutput.f90: module for writing solutions to tecplot files./external/: directory containing code for external libraries./makefile: makefile./make.compiler: defines compiler flags, 'included' inmakefile./lbm.cfg: example configuration file containing parameter defaults
Acknowledgement
This work was funded by the MENtOR project, a UKVLN project supported by the Engineering and Physical Sciences Research Council (EPSRC) of the UK. Grant reference number EP/S010378/1
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