MATLAB PrimerThird EditionKermit SigmonDepartment of MathematicsUniversity of FloridaDepartment of Mathematics • University of Florida • Gainesville, FL [email protected]1989, 1992, 1993 by Kermit SigmonOn the Third EditionThe Third Edition of the MATLAB Primer is based on version 4.0/4.1 of MATLAB.While this edition reflects an extensive general revision of the Second Edition, most sig-nificant is the new information to help one begin to use the major new features of version4.0/4.1, the sparse matrix and enhanced graphics capabilities.The plain TEX source and corresponding PostScript file of the latest printing of theMATLAB Primer are always available via anonymous ftp from:Address: math.ufl.edu Directory: pub/matlab Files: primer.tex, primer.psYou are advised to download anew each term the latest printing of the Primer since minorimprovements and corrections may have been made in the interim. If ftp is unavailableto you, the Primer can be obtained via listserv by sending an email message to [email protected] containing the single line send matlab/primer.tex.Also available at this ftp site are both English (primer35.tex, primer35.ps)andSpanish (primer35sp.tex, primer35sp.ps) versions of the Second Edition of the Primer,which was based on version 3.5 of MATLAB. The Spanish translation is by CelestinoMontes, University of Seville, Spain. A Spanish translation of the Third Edition is underdevelopment.Users of the Primer usually appreciate the convenience and durability of a bound copywith a cover, copy center style.(12-93)Copyrightc1989, 1992, 1993 by Kermit SigmonThe MATLAB Primer may be distributed as desired subject to the following con-ditions:1. It may not be altered in any way, except possibly adding an addendum givinginformation about the local computer installation or MATLAB toolboxes.2. It, or any part thereof, may not be used as part of a document distributed fora commercial purpose.In particular, it may be distributed via a local copy center or bookstore.Department of Mathematics • University of Florida • Gainesville, FL [email protected] is an interactive, matrix-based system for scientific and engineering numericcomputation and visualization. You can solve complex numerical problems in a fraction ofthe time required with a programming language such as Fortran or C. The name MATLABis derived from MATrix LABoratory.The purpose of this Primer is to help you begin to use MATLAB. It is not intendedto be a substitute for the User’s Guide and Reference Guide for MATLAB. The Primercan best be used hands-on. You are encouraged to work at the computer as you read thePrimer and freely experiment with examples. This Primer, along with the on-line helpfacility, usually suffice for students in a class requiring use of MATLAB.You should liberally use the on-line help facility for more detailed information. Whenusing MATLAB, the command help functionname will give information about a specificfunction. For example, the command help eig will give information about the eigenvaluefunction eig. By itself, the command help will display a list of topics for which on-linehelp is available; then help topic will list those specific functions under this topic for whichhelp is available. The list of functions in the last section of this Primer also gives most ofthis information. You can preview some of the features of MATLAB by first entering thecommand demo and then selecting from the options offered.The scope and power of MATLAB go far beyond these notes. Eventually you willwant to consult the MATLAB User’s Guide and Reference Guide. Copies of the completedocumentation are often available for review at locations such as consulting desks, terminalrooms, computing labs, and the reserve desk of the library. Consult your instructor or yourlocal computing center to learn where this documentation is located at your institution.MATLAB is available for a number of environments: Sun/Apollo/VAXstation/HPworkstations, VAX, MicroVAX, Gould, PC and AT compatibles, 80386 and 80486 com-puters, Apple Macintosh, and several parallel machines. There is a relatively inexpensiveStudent Edition available from Prentice Hall publishers. The information in these notesapplies generally to all of these environments.MATLAB is licensed by The MathWorks, Inc., 24 Prime Park Way, Natick, MA 01760,(508)653-1415, Fax: (508)653-2997, Email: [email protected]1989, 1992, 1993 by Kermit SigmoniiContentsPage1. Accessing MATLAB ............................................................. 12. Entering matrices ................................................................ 13. Matrix operations, array operations .............................................. 24. Statements, expressions, variables; saving a session ............................... 35. Matrix building functions ........................................................ 46. For, while, if — and relations .................................................... 47. Scalar functions ................................................................. 78. Vector functions ................................................................. 79. Matrix functions ................................................................. 710. Command line editing and recall ................................................. 811. Submatrices and colon notation .................................................. 812. M-files: script files, function files ................................................. 913. Text strings, error messages, input .............................................. 1214. Managing M-files ............................................................... 1315. Comparing efficiency of algorithms: flops, tic, toc ............................... 1416. Output format ................................................................. 1417. Hard copy ...................................................................... 1518. Graphics ....................................................................... 15planar plots (15), hardcopy (17), 3-D line plots (18)mesh and surface plots (18), Handle Graphics (20)19. Sparse matrix computations .................................................... 2020. Reference ...................................................................... 22iii1. Accessing MATLAB.On most systems, after logging in one can enter MATLAB with the system commandmatlab and exit MATLAB with