Algorithms and Parallel Computing

1.2 TOWARD AUTOMATING PARALLEL PROGRAMMING

We are all familiar with the process of algorithm implementation in software. When we write a code, we do not need to know the details of the target computer system since the compiler will take care of the details. However, we are steeped in think­ing in terms of a single central processing unit (CPU) and sequential processing when we start writing the code or debugging the output. On the other hand, the processes of implementing algorithms in hardware or in software for parallel machines are more related than we might think. Figure 1.1 shows the main phases or layers of implementing an application in software or hardware using parallel computers. Starting at the top, layer 5 is the application layer where the application or problem to be implemented on a parallel computing platform is defined. The specifications of inputs and outputs of the application being studied are also defined. Some input/output (I/O) specifications might be concerned with where data is stored and the desired timing relations of data. The results of this layer are fed to the lower layer to guide the algorithm development.

Figure 1.1 The phases or layers of implementing an application in software or hardware using parallel computers.

Layer 4 is algorithm development to implement the application in question. The computations required to implement the application ...