The multi-GPU Wetland DEM Ponding Model (WDPM)

Background

• WDPM simulates how runoff water is distributed across the Canadian Prairies
• WDPM has been generalized to take advantage of multiple GPUs
• A speedup of 2.39 has been observed using 4 GPUs with a real dataset
• By using leading computing paradigms, WDPM can perform difficult simulations

Folders and files

/ - Contains files describing the program:

• README.md - this file

/Code - Contains program source code files:

• wdpm_mulGPU.c - WDPM base code. Can be executed from the command line.
• wdpm_mulgpu_balanced.c - WDPM with additional workload balancing optimizations.
• runoff.cl - OpenCL kernel that does the water smoothing

/Data - Experimental data in the paper:

• The file names describe the experiment: the experiment group, module (add, substract, or drain), devices (GPU or CPU, and the number of devices), and systems (the input files)

Installation

OpenCL configuration

The WDPM requires OpenCL drivers in order to work properly. To download and install OpenCL for different platform, please check the following list:

• Intel CPU
• AMD CPU
• NVIDIA GPU
• AMD GPU

Compiling the code

The gcc compiler, version 11.4.0 or later, is recommended. Use the following command to compile the program:

gcc wdpm_mulGPU.c -o WDPM -lOpenCL

Running the code

The add, subtract, and drain modules take the following input arguments:

Add module

Argument	Type	Notes
DEM file name	string
Water file name	string	Optional - use NULL to omit
Output file name	string
Scratch file name	string	Optional - use NULL to omit
Depth of water to add (mm)	real
Water runoff fraction	real
Elevation tolerance (mm)	real
Parallel control	integer	Specify 0 for serial CPU and 1 for OpenCL
OpenCL options	integer	Specify 0 for OpenCL GPU and 1 for OpenCL CPU
Zero depth threshold (mm)	real
Maximum number of iterations	integer	Optional - use 0 to omit

Subtract module

Argument	Type	Notes
DEM file name	string
Water file name	string
Output file name	string
Scratch file name	string	Optional - use NULL to omit
Depth of water to remove (mm)	real
Elevation tolerance (mm)	real
Parallel control	integer	Specify 0 for serial CPU and 1 for OpenCL
OpenCL options	integer	Specify 0 for OpenCL GPU and 1 for OpenCL CPU
Zero depth threshold (mm)	real
Maximum number of iterations	integer	Optional - use 0 to omit

Drain module

Argument	Type	Notes
DEM file name	string
Water file name	string	Optional - use NULL to omit
Output file name	string
Scratch file name	string	Optional - use NULL to omit
Elevation tolerance (mm)	real
Drain tolerance (mm)	real
Parallel control	integer	Specify 0 for serial CPU and 1 for OpenCL
OpenCL options	integer	Specify 0 for OpenCL GPU and 1 for OpenCL CPU
Zero depth threshold (mm)	real
Maximum number of iterations	integer	Optional - use 0 to omit

Sample run using the add module

./WDPM add basin5.asc NULL water.asc NULL 10.0 1.0 1.0 1 0 0.005 0