Matlab FAQ - Interview Questions

Matlab FAQ - Interview Questions

WHAT IS MATLAB?

MATLAB is a high-performance language for technical computing. It integrates computation, visualization, and programming in an easy-to-use environment where problems and solutions are expressed in familiar mathematical notation.

Typical uses include:

 * Math and computation

 * Algorithm development

 * Modeling, simulation, and prototyping

 * Data analysis, exploration, and visualization

 * Scientific and engineering graphics

 * Application development, including Graphical User Interface building

WHAT ARE THE MATLAB SYSTEM PARTS?

The MATLAB system consists of five main parts:

 * The MATLAB language.

 * The MATLAB working environment.

 * Handle Graphics.

 * The MATLAB mathematical function library.

 * The MATLAB Application Program Interface (API).

EXPLAIN THE MATLAB LANGUAGE?

This is a high-level matrix/array language with control flow statements, functions, data structures, input/output, and object-oriented programming features. It allows both "programming in the small" to rapidly create quick and dirty throw-away programs, and "programming in the large" to create complete large and complex application programs.

EXPLAIN THE MATLAB WORKING ENVIRONMENT?

This is the set of tools and facilities that you work with as the MATLAB user or programmer. It includes facilities for managing the variables in your workspace and importing and exporting data. It also includes tools for developing, managing, debugging, and profiling M-files, MATLAB's applications.

EXPLAIN HANDLE GRAPHICS IN MATLAB?

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

EXPLAIN THE MATLAB MATHEMATICAL FUNCTION LIBRARY?

This is a vast collection of computational algorithms ranging from elementary functions like sum, sine, cosine, and complex arithmetic, to more sophisticated functions like matrix inverse, matrix eigenvalues, Bessel functions, and fast Fourier transforms.

EXPLAIN THE MATLAB APPLICATION PROGRAM INTERFACE (API)?

This is a library that allows you to write C and Fortran programs that interact with MATLAB. It include facilities for calling routines from MATLAB (dynamic linking), calling MATLAB as a computational engine, and for reading and writing MAT-files.

HOW TO ADD NOISE TO AN IMAGE IN MATLAB?

The function noise.m, now installed on ashland too, adds Gaussian, uniform, salt and pepper, additive or multiplicative noise to an image.

WHAT CAN WE USE MATLAB FOR?

1. Simple calculations

2. Plotting and analyzing mathematical relationships (2D and 3D)

3. List & Matrix Operations

4. Writing script files (a type of programming)

5. Symbolic manipulation of equations

6. Advanced visualization, animation and GUI interface tools

VECTORIZATION WHAT IS THAT IN MATLAB? HOW TO DO IT?

Thinking is terms of full matrices/vectors and also some related functions for that * Use of filter(), which works beautifully for some time series models

ON WHAT MACHINES MATLAB SHOULD BE RUN?

We will run it from sthelens, and only if sthelens is down, from cher, orsay or tiree. It works on other machines too, but some of the other machines have older versions of the OS and core dump upon exiting from matlab. Some other local machines with new setups work fine. Try your local machine. Matlab is blocked from running on the servers

EXPLAIN LATEX IN MATLAB?

Matlab already handles naturally simple LaTeX encodings that allow introducing Greek lettters or modifying the font size and appearance in plots.

CAN WE RUN MATLAB WITHOUT GRAPHICS?

Sometimes you may want to run scripts which contain plotting commands without displaying the plots and without going into the script to comment out the commands. An example: if you're working from home and it's too slow to run graphics over the network. You can play a simple UNIX trick: % setenv DISPLAY /dev/null % matlab

HOW TO CORRECTLY APPLY THE GRAPHICS PATCHES IN MATLAB?

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

HOW TO CALL MATLAB IN BATCH MODE?

This can be done from the command line or from a makefile. You need a script (filename.m). Just type at the command line, or include in the makefile: matlab<filename.m where filename.m can write to disk a figure, a binary, an ascii file, anything you want.

EXPLAIN ABOUT STRESS ANALYSIS IN MATLAB?

People working on these areas as a aerospace engineers should have familiarity and exposure to NASTRAN and MATLAB with knowledge on space environment and modeling of flexible dynamics. These aerospace engineers will be responsible to conduct stress analysis on metallic and composite structures. NASTRAN, IDEAD, Oracle and PATRAN proficiency level is required. Their duties also include on aircraft which are metallic and composite structures. This includes and understanding of control surface stiffness and loop calculations, finite element modeling (FEM), fatigue testing requirement and analysis.