Overview
========

Directories 1-3 correspond to tasks.

In each task, we are given some image files and we are asked to apply a Gaussian
blur filter to it.  Since operations on images are easy to parallelize, we can
use multiple threads for the blurring.  In all three cases we must save the
resulting image(s) in separate buffers and write them to a file.

Every task examines a different multithreading model, namely:

1. POSIX threads (see: pthreads(7))
2. OpenMP
3. OpenCL (GPU)