luxwj / parallel-relaxed-flooding-algorithm

Parallel Relaxed Flooding Algorithm (PRFA)

A GPU-based parallel algorithm for Voronoi diagram generation.

Usage

1. mkdir build
2. cd build
3. cmake ..
4. make
5. ./PRFA

Input & Output

Input: Randomly generated data or txt file with point data.

• When using txt file as input, set USE_IMAGE_INPUT to true and modify the values of IMAGE_INPUT_PREFIX and IMAGE_FILE_NUMBER.

Output: Set PRINT_VORONOI to true and modify the value of IMAGE_OUTPUT_PREFIX.

Parameter List

In parameter.h,

Parameter	Description
DTYPE	Data type of point coordinates. Only use short in this program.
DIM	Dimension of point data. 2D in this program.
int PIC_WIDTH	Image width. 1024, 2048, 4096, and 8192 are tested.
int SITES_NUMBER	Reference point number for random data. It should be set to 0 when using image (txt) input.
E_DISTRIBUTION DISTRIBUTION	Type of the random point distribution. Uniform, normal, clusters, or alignments.
RNG_CLUSTER_COUNT	Parameter for the random number generator. Cluster count in the clusters distribution.
RNG_LINE_COUNT	Parameter for the random number generator. Alignment (Line) count in the alignments distribution.
PRFA_BLOCK_SIZE_2D_X	Block size x of the PRFA CUDA kernel.
PRFA_BLOCK_SIZE_2D_Y	Block size y of the PRFA CUDA kernel.
THREAD_DIM	Edge length of a subregion. The footmark variable in the PRFA kernel is related with this parameter.
K	Relevant point count for each subregion.
COMPRESS_KD_NODE	If true, use 1 bit in the x- (y-) coord of a node to represent the existence of the left (right) child.
TREE_H	Height of the k-d tree. It should be set to log2(2, SITES_NUMBER).
MARKER	A sentinel value.

In main.cpp,

Parameter	Description
bool CHECK_FAULT	If true, run brute force algorithm to verify the results of PRFA. IF false, only run PRFA.
bool PRINT_FAULT	If true, print all incorrect pixel coordinates. Only available when CHECK_FAULT == true.
bool ITER_TEST	If true, run PRFA multiple times to get an average result. Notice that the result of the first iteration is discarded. If false, only run PRFA one time.
int ITER_COUNT	Count of iterations when ITER_TEST == true.
bool USE_IMAGE_INPUT	If true, take a txt file as point input. Notice that SITES_NUMBER should be set to 0 and PIC_WIDTH should be set to the image's size. If false, use random point data.
bool PRINT_VORONOI	If true, print the pixel labels of the diagram into a file.
string IMAGE_INPUT_PREFIX	Input image (txt) file directory.
string IMAGE_OUTPUT_PREFIX	Output image (txt) file directory.
string IMAGE_FILE_NUMBER	Image (txt) file name.

Random Number Generator

For randomly generated data, choose between four distributions. Assume that the point number is $N$.

• Uniform distribution.
• Normal distribution. The standard deviation is $0.2W$, where $W$ is the image width.
• Clusters distribution, cluster number = $\sqrt{N}$.
• Alignments distribution, alignment number = $\sqrt[3]{N}$.