Other online documents available:

• Invoking Matlab on the HPs
• Running Background Jobs
• Matlab Help Desk
• Mathtools.net (MathWorks Technical Computing Portal)

Please note that this page was written for Matlab version 5.0a, and this site is now running Matlab 6.5. This update was not a major shift in the way Matlab is run, but some of the Matlab and Simulink features, as well as some of the toolboxes, have been changed. If you note a discrepancy, please report it to the class instructor.

1. What is MATLAB?
2. Accessing MATLAB at ER4?
3. An Introductory Demonstration
4. Making and Printing Graphs
   1. Example Signal
   2. Plot Commands
   3. Printing
   4. Importing Data for Graphing
5. Getting Help
6. M-files
   1. Script Files
   2. Function Files
   3. Background Processes
7. Controls Toolbox
8. Signal Processing Toolbox
9. Finishing
1. Using MATLAB to Plot Data Generated by Other Programs
2. Man Pages

MATLAB is a high-performance, interactive software package for scientific and engineering numeric computation. MATLAB integrates numerical analysis, matrix computation, signal processing, and graphics in an easy-to-use environment without traditional programming.

The name MATLAB stands for matrix laboratory. MATLAB was originally written to provide easy access to the matrix software developed by the LINPACK and EISPACK projects.

MATLAB is an interactive system whose basic data element is a matrix that does not require dimensioning. Furthermore, problem solutions are expressed in MATLAB almost exactly as they are written mathematically.

MATLAB has evolved over the years with input from many users. MATLAB TOOLBOXES are specialized collections of MATLAB files designed for solving particular classes of functions. These packages are currently available:

Log onto a workstation.

Use the mouse button to view the Root Menu. Drag the cursor to "Utilities" then to "Matlab." Release the mouse button. You are now running the MATLAB interactive software package. The prompt is a double "greater than" sign. You may use emacs line editor commands and the arrow keys while typing in MATLAB.

MATLAB can also be started from any terminal window (dtterm), with display capabilities, using the command matlab.

Execute the following command to view a quick introduction to MATLAB.

>> demo

Select MATLAB in the left hand window and then "Basic Matrix Operations" under Matlab in the right hand pane. Now follow the instructions given in the matlab pop-up window.

Generate 500 samples of a sine wave of frequency 60 Hz and sampled at 8 kHz.

>> n = [0:499]/8000;
>> x=sin(2*pi*60*n);

>> plot(x)

>> plot(n,x)

>> plot(n,x)
>> title('Title of plot')
>> xlabel('seconds')
>> ylabel('amplitude')
>> grid

>> plot(n(1:50),x(1:50))

>> subplot(2,1,1),plot(x,n)
>> title('plot a')
>> subplot(2,1,2),plot(x(1:50))
>> title('plot b')

plot, semilogx, semilogy, stem, hold, mesh, contour

For a colorful demo for MATLAB graphics, type

>> demo

>> print temp -f1

dtterm> ghostview temp.ps

in MATLAB Window in workstation window (dtterm)

>> print temp -f1 dtterm> lp temp.ps

Data generated by MATLAB can be stored, transferred and reloaded into MATLAB using files with the .mat suffix. For example, load and plot the canine electrocardiogram (this file will not display in your browser window properly... right click on the link and "save link as" to your home account) stored in the vector "ecg" in a file named canine.mat.

>> load canine
>> plot(ecg)

>> more on
>> help help
>> help fft
>> more off

>> type sinc

AVOID LOOPS

tt

sum

prod

.*

.^

:

toeplitz

For example, the sinusoid signal in Section VI, Subsection 1 was generated without loops.

nice +20 matlab < inputfile > outputfile &

>> more on; help control

>> help ctrldemos

>> more on; help signal

>> help SIGDEMOS
>> filtdem
>> moddemo

>> quit

/* This file may be compiled using the format:

       gcc filename.c -o exefile -lm

   Running this program creates a file named "outvar.dat".  The
   data for a cosine and sine function is calculated and saved
   as three columns of numbers.

   To plot the data within MATLAB, you may use the following
   from a MATLAB window:

>> load outvar.dat
>> x = outvar(:,1);
>> y = outvar(:,2);
>> z = outvar(:,3);
>> plot(x,y)
>> hold on
>> plot(x,z)
>> hold off
*/

#include         /* standard Input/Output */
#include        /* standard library      */
#include          /* math library          */

main()
{
  double x,y,z;           /* variables used */
  FILE *fp;               /* file pointer   */

/* Check to see if there are any file errors.        */
/* This will either create a new file OUTVAR.DAT, or */
/* write over an existing version of the file.       */
  if ( (fp = fopen("outvar.dat", "w")) == NULL)
    {
      printf("Cant open OUTVAR.DAT \n");
      exit(1);
    }

/* This loop is used to save y=cos(x).*/
  for(x=0; x<=10; x += 0.1)
    {
      y = cos(x);
      z = sin(x);
      fprintf(fp, "%f %f %f",x,y,z);   /* save the x and y values */
      fprintf(fp, "\n");               /* create a line break     */
    }
  fclose(fp);                          /* close the file */
}

Press here to view the matlab.c source code. To save the file, select "Save As" from the "File" menu of netscape.

• matlab
• cmex
• fmex