Parallel programming models exist as an abstraction of hardware and memory architectures. In fact, these models are not specific and do not refer to any particular types of machines or memory architectures. They can be implemented (at least theoretically) on any kind of machines. Compared to the previous subdivisions, these programming models are made at a higher level and represent the way in which the software must be implemented to perform parallel computation. Each model has its own way of sharing information with other processors in order to access memory and divide the work.

In absolute terms, no one model is better than the other. Therefore, the best solution to be applied will depend very much on the problem that a programmer should address and resolve. The most widely used models for parallel programming are as follows:

• Shared memory model
• Multithread model
• Distributed memory/message passing model
• Data-parallel model

In this recipe, we will give you an overview of these models.