Steps in Function Decomposition

In software engineering whenever we have complex systems or large systems that we want to decompose into small subsystems or modules or if we want to turn complex systems into simple systems, then we can use function decomposition. The following are the steps that are required in any function decomposition:

1. Identifying the Main Functions

This is the first step in function decomposition. In this system, we try to identify the malfunctions of the system and what this means in this step, we try to understand what the system does and what the working it is supposed to after this we move to the next step.

Identifying the main functions means that we try to figure out exactly what a system is supposed to do and also figure out how it works. It means understanding the particular job of the system. For example, if we talk about a car the main function of a car can include moving forward stopping and turning etc similarly we try to identify the main functions for this method as well.

2. Dividing the Main Functions

• In this step, we try to divide the main functions of the system and we try to divide the complex main functions so that we can convert them into simple sub-functions then we move to the next step.
• Once we understand the first step and know what the system is we break down the main jobs into two tasks which are smaller and simpler. The main reason behind this step is that it helps us to understand the functions more easily as we understood above step by an example of a car in this step we can break down the moving forward task into smaller tasks such as a break-in accelerating or steering etc.

3. Define the Relationships

• In this step, we define the relationship among the various subfunctions and the main function, this helps us to understand how the various functions are connected and interact together so that we can achieve the end goal of the system.
• So now we have defined the malfunctions and also managed to break the tasks into smaller functions so now that we have smaller tasks we can look at how they have connected the reason for defining this relationship is because this helps us to see how everything works together to achieve the goal of the system.

4. Represent the Relationships

• After defining the relationships, we try to represent the relationship among the functions so that we can have a pictorial view and understanding of the relationship between the functions.
• In this, we make a picture or a simple diagram that can be used to show how all of the tasks are connected. This process is important because it helps us to visualize how the system is functioning, after this step we move to the final step of function decomposition.

5. Refine the Functional Decomposition

• This is the final step of the function decomposition. In this step, we review the system’s functional block diagram and we also try to add some modifications according to our needs so that the system and its functions do the work that they are supposed to.
• In this step, we also review our diagram and then we make any necessary changes that are required to make sure that the system and its tasks are doing exactly what they are intended to do. After this refining of the functional decomposition, we can say that we have successfully decomposed a particular system.

The function decomposition is important in software engineering because it helps us to create more manageable modules. This decomposition of functions in chapter engineering also helps us to understand and design the software systems more easily. In this article, we are going to understand function decomposition in detail.