MATLAB Interview Questions

A list of frequently asked MATLAB Interview Questions and Answers are given below.

1) What is MATLAB?

MATLAB is a high-performance language for numerical computing. It consolidates calculations, visualization, and programming in an easy-to-use environment where problems and answers are expressed in familiar binary notation.

It contains:

• Math and computation
• Algorithm development
• Modeling, simulation, and prototyping
• Data analysis, exploration, and visualization
• Scientific and engineering graphics
• Application development, containing Graphical User Interface building

2) Explain MATLAB API (Application Program Interface)?

MATLAB API is a library that allows us to write Fortran and C programs that interact with MATLAB. It includes the facilities for calling routines from MATLAB, for reading and writing Mat files and calling MATLAB as a computational engine.

3) What is The MATLAB working environment?

This is the set of tools and facilities that we work with as the MATLAB client or programmer. It contains facilities for managing the variables in our workspace and importing and exporting data. It also contains tools for developing, managing, debugging, and profiling M-files, MATLAB?s applications.

4) What is Simulink?

Simulink is an add-on product to MATLAB, it provides an interactive, simulating, graphical environment for modeling and analyzing dynamic systems.

5) Explain how polynomials can be represented in MATLAB?

A polynomial in MATLAB is indicated by a vector. To create a polynomial in MATLAB, enter each coefficient of the polynomial into the vector in descending order.

6) Explain handle graphics in MATLAB?

This is the MATLAB graphic system. It contains high-level commands for two-dimensional and three-dimensional data visualization, image processing, animation, and display graphics. It also contains low-level commands that allow us to customize the display of graphics fully as well as to build complete Graphical User Interfaces on your applications.

7) What is Get and Set in MATLAB?

Get and Set are indicated to as getter and setter functions. For assigning properties, setter functions are used while for accessing features, getter functions are used.

8) Can Multi-dimensional arrays support in MATLAB?

No, it does not support. It supports the two-dimensional type of matrix. An option is an option with the programmer to write the function of their own to utilize multi-dimensional array features as per the application of use.

9) What are the types of Loops does MATLAB provides?

MATLAB provides loops like

• While Loop
• For Loop
• Nested Loops

10) What is 3D-Visualization elements in MATLAB?

3D-Visualization elements allow MATLAB to handle 3D graphics.

• Surface and Mesh Plots: It includes plot matrices, visualizes functions, and color maps.
• View Control: It is used to control camera viewpoint, rotation, zooming, and aspect ratio and set axis limits.
• Lighting: It is used for adding and controlling scene lighting.
• Transparency: It is used to specify object transparency.
• Volume Visualization: It is used for the volume data grid.

11) What is memory management functions in MATLAB?

Following are the lists of memory management functions.

• Clear: It removes variables from memory.
• Pack: It saves the existing variables to disk, and then reloads them contiguously.
• Save: It selectively persists variable to disk.
• Load: Reloads a data file stored with the save function.
• Quit: Exits MATLAB and all allocated memory to the system.

12) What are the basic Plots and Graphs of MATLAB?

Following table defines basic plots and graphs:

• Box: Axis Border
• Errorbar: Plots error bars along the curve.
• Hold: Retains the current graph while adding a new graph.
• Line: Creates a line object.
• LineSpec (Line Specification): Syntax of Line Specification String.
• Loglog: Log to the log-scale plot.
• Plot: 2-D Line Plot.
• Plot3: 3-D Line Plot.
• Plotyy: 2-D Line plots with y-axis on both the left and right side
• Polar: Polar coordinate plot.
• Semilogx: Semilogarithmic plot.
• Semilogy: Semilogarithmic plot.
• Subplot: It creates an axis in tiled positions.
• Xlim: Sets or queries x-axis limits.
• Ylim:: Sets or queries y-axis limits.
• Zlim: Sets or queries z-axis limits.

13) What are the four essential functions to solve Ordinary Differential Equations (ODE)?

The four primary functions that MATLAB has to solve ODE's are

Quad
Quad8
ODE23
ODE45

14) What is latex in MATLAB?

MATLAB already deals naturally with simple latex encoding that enables introducing Greek letters or changing the font size and displays in plots.

15) What do you mean by M-file in MATLAB?

M-files are nothing but just a plain ASCII script that is interpreted at run time. We can say these are the subprograms stored in text files with .m extensions and are known as M-files. M-files are used for most of the MATLAB development, and platform independence and maintainability. It is parsed once and "just-in-time" compiled, but it is also transparent to the customer.

16) What are the MEX files?

MEX files are native C or C++ files that is dynamically connected directly into the MATLAB application at runtime. It allows using C, C++, and Fortran programs in MATLAB. They must be compiled for each hardware structure on which they are to be run.

17) What are the standard toolboxes present in MATLAB and how these toolboxes can be accessed?

Various types of toolboxes available are:

• Control Systems
• Fuzzy Logic
• Image Processing
• LMI Control
• Neural Networks
• Optimization
• Partial Differential Equation
• Robust Control
• Signal Processing
• Statistics
• Symbolic Math
• System Identification
• Wavelets

To create this Toolbox, go to the MATLAB Start menu, then go to the Toolboxes submenu, then select the Toolbox which we want to use.

18) How to Correctly Apply the Graphics Patches in MATLAB?

Open a LOCAL MACHINE window and type: xhost +ashland # Add the following code series just before the plot function that was giving our problems: figure? set(gcf,'renderer','zbuffer') ? [s, w] = unix ('echo $DISPLAY') ? set (gcf,'XDisplay', w) ?

19) What Is Xmath?

Xmath is an interactive design and graphics environment for Xwindow?s workstations.

Following are the Xmath features:

• Scripting languages with OOP features.
• Libraries that are LNX and C language compatible.
• Debugging tools with GUI features.
• Color graphics can be pointed and clickable.
• A specific layer is feasible that is programmable for MOTIF GUI.

20) What Is Pseudo-Random Binary Sequence and Numeric Precision In MATLAB?

Pseudorandom binary sequence: A form of creating an M-file in the new Frequency Domain System Identification Toolbox, for a specified set of lengths (2^2-1 to 2^30-1) is called a pseudo-random binary sequence. It is also called a mlbs (Maximum Length, Binary Sequence).

Numeric precision: Numeric quantities that are represented as double-precision floating-point numbers is called numeric precision. In systems, such numbers have 53 significant binary bits, which is about 15 or 16 decimal digits.

21) Can We Run MATLAB without Graphics?

Sometimes we may want to run scripts that involve plotting commands without showing the plots and without going into the script to comment out the commands.

An example: if we are working from home and it's too slow to run graphics over the network. We can play a simple UNIX trick:
%setenv DISPLAY /dev/null % matlab

22) What is a P-code?

Pcode is a prepared and encoded version of the M-file. It stores the load time of the function. This is most likely not an issue except for very high M-files since most are parsed only once anyway. Pcode also lets us hide the source code from others. There is no way to change Pcode back to the M-file source. Pcode is platform-independent.

23) Explain about the mentioned tools in MATLAB: who, whos, pi, eps, type.

Who: It will show you all the variables you have currently defined.

whos: It will show you the variables, their sizes, and some other info.

pi: It is a function that returns the equation of pi.

eps: It is a function that returns MATLAB?s lowest floating-point number. This is useful if we have a vector that might include zeros that are going to wind up in the denominator of something. If we add eps to the vector, you aren't adding anything significant, but we won't run into a divide by zero problems anymore

Type: function name for any function in MATLAB?s search path lets us see how that function is written.

24) What Is Stress Analysis in MATLAB?

MATLAB is used in aerospace engineering, space environment.

MATLAB is suitable for flexible dynamics.

These domain experts conduct stress analysis on various operations like metallic and composite structures.

To analyze the stress, NASTRAN, IDEAD, Oracle, and PATRAN levels of proficiency are required.

The functions are also used on aircraft that is metallic structure.

The stress analysis contains control surface stiffness understanding, loop evaluation, finite item modeling, and fatigue testing requirement and analysis.

25) How can the source code can be executed on MATLAB?

By default, the code is generally stored with in (.m) extension, which is anchored however if the customer needs it to be put away in a more anchored way then he can attempt the accompanying methods:

1. Influence it as P-to code: Convert a few of the most significant part of our source code files to the text darkened shape known as P-code document (from its. p document extension), and disseminate our program code in this configuration.
2. Accumulate into the double solution: Compile your source code files using the MATLAB Compiler to produce an independent function. Appropriate the last to end-user of our application.