MATLAB Interview Questions

Basic MATLAB Interview Questions for Freshers

1. What do you understand by MATLAB API?

The MATLAB data API allows the applications not written in MATLAB to interact with MATLAB-driven applications. It will enable us to make API Calls and access the resources.

2. Discuss memory management functions in MATLAB.

Memory management is used to manage the resources of a computer. The memory is assigned whenever an application is running and freed when the work is done. The following functions are prominent in MATLAB-

Clear- It removes the memory occupied by the variable.

Pack- It saves the existing variables and reloads them on demand.

Load- It reloads the data previously saved.

Save- It simply saves the data.

Quit- It exits and frees the memory occupied by MATLAB.

3. What are M-Files and MEX files?

M-Files are ASCII scripts. They are interpreted at the run-time. They have a significant role to play in the development of MATLAB. These are also platform-independent.

MEX Files are written in C or C++. They are joined with the MATLAB files at the run-time.

4. How do we perform Stress Analysis in MATLAB? 

Stress Analysis using MATLAB is usually performed in aerospace and space environments.

NASTRAN, Oracle, and IDEAD levels of proficiency are essential to analyze stress.

5. Explain the concept of Loops in MATLAB.

While Loop- Continues to repeat a statement while a given condition is true.

For Loop- Executes multiple times until a condition is satisfied.

Nested Loop- You can use loops inside other loops.

6. Discuss XMath in detail.  

X-Math is an interactive scripting tool widely used in MATLAB. The features present in X-Math are-

Object-oriented Programming Features

Compatible Libraries with C and LNX

Debugging facility with extensive Graphical User Interface.

7. How is code commented in MATLAB? 

Comments are written in code to make understanding easier.

The syntax is -

“ % Welcome to Coding Ninjas. ”

8. How do we plot graphs in MATLAB? 

The following functions allow the user to plot graphs-

• Box:  Border of Axis
• Errorbar: Constructs error bars.
• Hold: Preserves the current graph while adding a new one.
• Line: Creates a line.
• Plot: 2-D Line Plot.
• Plot3: 3-D Line Plot.
• Xlim: Defines x-axis limits.
• Ylim::Defines y-axis limits.
• Zlim: Defines z-axis limits.

9. How to handle images and graphics in MATLAB?

MATLAB provides extensive features for graphics modification. Both high-level and low-level commands are present. The low-level controls allow us to create a GUI from scratch and make changes. At the same time, the high-level commands will enable us to process images, visualize data, and perform animations.

10. Write a code to work with the matrix in MATLAB.

a = [ 11 12 13 14 ; 12 13 14 15 ; 13 14 15 16 ; 14 15 16 17 ]

This is a method to create a 4X4 Matrix. The output will look like this-

a =

      11     12     13     14     

      12     13     14     15     

      13     14     15     16     

      14     15     16     17  

11. What is Classification accuracy? How do we calculate it?

Classification Accuracy means the count of the data that is correctly classified. This is how we can perform Accuracy Calculations in MATLAB-

% out= evalfis( fis, in);
p = round(out);
acc_count = nnz( p==in); 
acc = acc_count/length(in);

12. What is Simulink in MATLAB? 

Simulink is an additional product in MATLAB. Users can use it to provide a graphical and interactive environment to analyze dynamic models.

13. What do you mean by Interpolation and Extrapolation? 

Extrapolation means determining the value of an unknown quantity that is not clearly stated by the current information.

Interpolation, on the other hand, means estimating a value with the help of two given values.

14. What are housekeeping functions? Mention their significance.  

Housekeeping functions are the ones that do not play a vital role in Mathematics but come in handy while programming.

Some examples of Housekeeping functions are as follows-

ceil(x) 
fix(x) 
floor(x) 
length(a) 
mod(x,y) 
rem(x,y) 

15. What are neural networks, and how are they used in MATLAB? 

A neural network is a replica of the human brain. A neural network learns from previously available information and can be trained to recognize patterns, classify, and predict trends.

MATLAB toolbox provides apps and command line functions to allow working with neural networks. After generating the neural networks, users can automatically create MATLAB code for performing operations like regression, clustering, time series analysis, etc. 

MATLAB Interview Questions for Experienced

16. Explain the “Fuzzy Logic” toolbox. 

The fuzzy Logic toolbox provides MATLAB functions and ease of access. It allows analyzing, plotting, and simulating systems based on fuzzy logic. It performs the above tasks using a Simulink block. The toolbox makes it easy for users to interpret complex models using simple reasons.

17. How can we visualize 3-D elements in MATLAB? 

MATLAB can handle 3-D visualization with the following features-

Lighting Users can add and control scene lighting.

Transparency It is used for the determination of object transparency.

Volume Visualisation It determines the volumes of the grid.

Surface and Mesh Plots It handles plotting, matrices, and color maps.

18. Which programs are allowed in MATLAB?

MATLAB permits Scripts and Functions.

• Scripts: It is a file saved with a .m extension. It doesn’t accept inputs and doesn’t return any outputs.
• Functions: The functions can accept input and return sound outputs.

19. How to read a CSV file in MATLAB?

CSV means Comma comma-separated values. In the previous versions of MATLAB csvread command was used. In the newer versions, it has been replaced by a read matrix.

Syntax:

CN= readmatrix(filename)

20. What is the procedure for creating a GUI in MATLAB?

1. Select File > Preferences > GUIDE.
2. Select the “Show names” feature in the component palette.

Following the above steps, The user can create a GUI in MATLAB.

21. Explain the TEXTREAD function in MATLAB.

It allows you to read the text with flexibility. There is an option of ignoring comments, skipping lines at the start, and other additional features.

22. What is the basic idea behind solving differential equations in MATLAB?

The differential equations can be solved using proper mathematics and syntax. For greater accuracy, we use some ode solvers, namely ode23, ode45, ode15s, and ode23s.

Syntax-

[t, y] = ode45(@Name_of_function, tspan, n0)

23. How are polynomials expressed in MATLAB?

Polynomials are equations of a single variable with different components.  

For example, [1 -3 2] corresponds to x2 – 3x + 2. Some of the functions are:

Poly, polyeig, polyfit, residue, roots, polyval, etc.

24. What is the difference between * and .* in MATLAB?

• * is a vector or matrix multiplication; the operands should follow the rules of matrix multiplication in this case.
• .* is an element-wise multiplication. Matrix size should be equal to carry out this operation.

25. Why are Categorical Arrays more beneficial than Character Arrays?

Categorical arrays are more memory efficient than character arrays. Unlike, Character arrays that allow just alphabetical ordering, they offer precise mathematical arrangement.

In categorical arrays, we can make comparisons easily by using (==), while we need to use strcmp to compare in character arrays.

26. What do you mean by set and get functions in MATLAB?

Set means setter function. It is used to appoint properties in MATLAB.

Get stands for getter function. It is used to obtain properties in MATLAB.

27. What is the main difference between regular and cell arrays?

In simple language, regular arrays contain the same elements; in cell arrays, the parts are heterogeneous, that is, different elements.

Cell Arrays are used when-

• We have different types in your array.
• We are not sure whether you might extend it to another type in the future.
• We are working with objects that have an inheritance pattern.

Regular Arrays are used when-

• We have the same type of elements.
• We will not change the data type of the array in the future.
• We are working with objects that have no inheritance.

28. What is the purpose of P-code?

P-code files are executable obscured files. It gives the feature of hiding the source code from others. P-code is platform-independent as well.

29. What are the methods to secure your code in MATLAB?

Transform it to P-Code- Converting the code to P-code increases security as the code is hidden from others. You can convert a few lines of code or a significant chunk of code to a P-code document (.p extension).

Accumulate into a double solution- You can use MATLAB compiler to compile your source code and create an independent application.

30. How many breakpoints are there in MATLAB? Explain.

• Standard Breakpoint: F12 key is used to pause the program's execution according to the user's will.
• Conditional Breakpoint: The program stops execution only where a specific condition is met.
• Error Breakpoint: The program pauses its execution when it encounters an error situation.

MATLAB MCQ

1. What does MATLAB stand for?

• A) Matrix Laboratory
• B) Machine Learning and Tool Algorithm Basics
• C) Machine and Language Toolbox
• D) Mathematical and Technical Analysis

Answer: A) Matrix Laboratory

2. Which of the following is used to create a 2D plot in MATLAB?

• A) plot()
• B) graph()
• C) draw()
• D) chart()

Answer: A) plot()

3. How can you clear all variables in the MATLAB workspace?

• A) clear all
• B) reset all
• C) delete all
• D) remove all

Answer: A) clear all

4. Which data structure is MATLAB primarily designed to work with?

• A) Lists
• B) Arrays
• C) Trees
• D) Stacks

Answer: B) Arrays

5. What is the default variable name in MATLAB when an output is not assigned?

• A) ans
• B) output
• C) res
• D) result

Answer: A) ans

6. Which of the following is used for element-wise multiplication in MATLAB?

• A) *
• B) .*
• C) /
• D) //

Answer: B) .*

7. How do you add comments in MATLAB?

• A) //
• B) /* */
• C) %%
• D) %

Answer: D) %

8. Which function is used to find the size of a matrix in MATLAB?

• A) length()
• B) dimension()
• C) size()
• D) range()

Answer: C) size()

9. How do you save your workspace variables in MATLAB?

• A) save filename
• B) store filename
• C) backup filename
• D) archive filename

Answer: A) save filename

10. What command is used to stop the execution of an infinite loop in MATLAB?

• A) halt
• B) break
• C) stop
• D) exit

Answer: B) break

Frequently Asked Questions

What are the Viva questions in MATLAB?

In a MATLAB Viva, common questions include the purpose of MATLAB, the use of arrays and matrices, plotting functions, and the application of loops. You may also be asked to explain basic commands like plot(), size(), or clear.

What are the basics of MATLAB?

The basics of MATLAB include understanding its workspace, syntax for creating variables, working with arrays and matrices, plotting data, and using functions like plot(), size(), and clear. It is essential to grasp MATLAB's core commands and operations.

What is MATLAB full form?

MATLAB stands for "Matrix Laboratory." It is a programming platform designed for engineers and scientists to analyze and design systems and products that use mathematical algorithms.

What is MATLAB used for?

MATLAB is used for numerical computation, data analysis, visualization, and algorithm development. It is widely applied in engineering, scientific research, signal processing, and machine learning.

Why is MATLAB so popular?

MATLAB is popular due to its simplicity for handling matrix operations, its vast library of pre-built functions, powerful visualization tools, and widespread use in academic and professional fields like engineering, data analysis, and research.

Why do we use MATLAB Simulink?

MATLAB Simulink is used for modeling, simulating, and analyzing dynamic systems. It allows users to design and test control systems, signal processing algorithms, and multi-domain models in an interactive graphical environment.

What is the difference between MATLAB and Simulink?

MATLAB is a programming language used for numerical computation, while Simulink is a graphical environment used for modeling, simulating, and analyzing multi-domain dynamic systems. Simulink operates on top of MATLAB and enhances system design capabilities.

Conclusion 

In this article, we thoroughly discussed the MATLAB interview questions. We started with the understanding of what is Matlab and later in the article also looked at MCQ questions for Matlab. 

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