Calculates the distribution of color value from data of an image
The distribution is calculated per exact color value. Color with B,G,R value (0,0,0) is different with (0,0,1). If the image has 2 pixel with color (0,0,0), then the value of color (0,0,0) is 2.
Calculate distribution of colors in serial.
Calculate distribution in parallel with omp.h (OpenMP library in C/C++)
omp_get_wtime - to calculate execution time
#pragma omp parallel for - to parallelize the for loop
#pragma omp atomic - to let the processor know that this operation is atomic (only one thread can get access to its content at a time)
Calculate distribution in parallel with mpi.h (OpenMPI library in C/C++)
MPI_Wtime - to calculate execution time
MPI_Bcast - to broadcast the size of image
MPI_Scatterv - to give each processor its scattered data to be processed, each processor get relatively equal amount of data
MPI_Reduce - to collect calculation from each processor and accumulate them
Added three calculation in OpenMPI:
- distribution calculation of blue color value,
- distribution calculation of green color value,
- distribution calculation of red color value