Press, Teukolsly, Vetterling, Flannery - Numerical Recipes in C, страница 3

An attractive feature of this approach, we think, is thatthe reader can use the book at increasing levels of sophistication as his/her experiencegrows. Even inexperienced readers should be able to use our most advanced routinesas black boxes. Having done so, we hope that these readers will subsequently goback and learn what secrets are inside.If there is a single dominant theme in this book, it is that practical methodsof numerical computation can be simultaneously efficient, clever, and — important— clear.

The alternative viewpoint, that efficient computational methods mustnecessarily be so arcane and complex as to be useful only in “black box” form,we firmly reject.Our purpose in this book is thus to open up a large number of computationalblack boxes to your scrutiny. We want to teach you to take apart these black boxesand to put them back together again, modifying them to suit your specific needs.We assume that you are mathematically literate, i.e., that you have the normalmathematical preparation associated with an undergraduate degree in a physicalscience, or engineering, or economics, or a quantitative social science. We assumethat you know how to program a computer.

We do not assume that you have anyprior formal knowledge of numerical analysis or numerical methods.The scope of Numerical Recipes is supposed to be “everything up to, butnot including, partial differential equations.” We honor this in the breach: First,we do have one introductory chapter on methods for partial differential equations(Chapter 19). Second, we obviously cannot include everything else.

All the so-called“standard” topics of a numerical analysis course have been included in this book:xivxvPreface to the First Editionlinear equations (Chapter 2), interpolation and extrapolation (Chaper 3), integration(Chaper 4), nonlinear root-finding (Chapter 9), eigensystems (Chapter 11), andordinary differential equations (Chapter 16). Most of these topics have been takenbeyond their standard treatments into some advanced material which we have feltto be particularly important or useful.Some other subjects that we cover in detail are not usually found in the standardnumerical analysis texts.

These include the evaluation of functions and of particularspecial functions of higher mathematics (Chapters 5 and 6); random numbers andMonte Carlo methods (Chapter 7); sorting (Chapter 8); optimization, includingmultidimensional methods (Chapter 10); Fourier transform methods, including FFTmethods and other spectral methods (Chapters 12 and 13); two chapters on thestatistical description and modeling of data (Chapters 14 and 15); and two-pointboundary value problems, both shooting and relaxation methods (Chapter 17).The programs in this book are included in ANSI-standard C. Versions of thebook in FORTRAN, Pascal, and BASIC are available separately.

We have moreto say about the C language, and the computational environment assumed by ourroutines, in §1.1 (Introduction).AcknowledgmentsMany colleagues have been generous in giving us the benefit of their numericaland computational experience, in providing us with programs, in commenting onthe manuscript, or in general encouragement. We particularly wish to thank GeorgeRybicki, Douglas Eardley, Philip Marcus, Stuart Shapiro, Paul Horowitz, BruceMusicus, Irwin Shapiro, Stephen Wolfram, Henry Abarbanel, Larry Smarr, RichardMuller, John Bahcall, and A.G.W. Cameron.We also wish to acknowledge two individuals whom we have never met:Forman Acton, whose 1970 textbook Numerical Methods that Work (New York:Harper and Row) has surely left its stylistic mark on us; and Donald Knuth, both forhis series of books on The Art of Computer Programming (Reading, MA: AddisonWesley), and for TEX, the computer typesetting language which immensely aidedproduction of this book.Research by the authors on computational methods was supported in part bythe U.S.

National Science Foundation.October, 1985William H. PressBrian P. FlannerySaul A. TeukolskyWilliam T. VetterlingLicense InformationRead this section if you want to use the programs in this book on a computer.You’ll need to read the following Disclaimer of Warranty, get the programs onto yourcomputer, and acquire a Numerical Recipes software license. (Without this license,which can be the free “immediate license” under terms described below, the book isintended as a text and reference book, for reading purposes only.)Disclaimer of WarrantyWe make no warranties, express or implied, that the programs containedin this volume are free of error, or are consistent with any particular standardof merchantability, or that they will meet your requirements for any particularapplication. They should not be relied on for solving a problem whose incorrectsolution could result in injury to a person or loss of property.

If you do use theprograms in such a manner, it is at your own risk. The authors and publisherdisclaim all liability for direct or consequential damages resulting from youruse of the programs.How to Get the Code onto Your ComputerPick one of the following methods:• You can type the programs from this book directly into your computer.

In thiscase, the only kind of license available to you is the free “immediate license”(see below). You are not authorized to transfer or distribute a machine-readablecopy to any other person, nor to have any other person type the programs into acomputer on your behalf. We do not want to hear bug reports from you if youchoose this option, because experience has shown that virtually all reported bugsin such cases are typing errors!• You can download the Numerical Recipes programs electronically from theNumerical Recipes On-Line Software Store, located at http://www.nr.com, ourWeb site.

They are packaged as a password-protected file, and you’ll need topurchase a license to unpack them. You can get a single-screen license andpassword immediately, on-line, from the On-Line Store, with fees ranging from$50 (PC, Macintosh, educational institutions’ UNIX) to $140 (general UNIX).Downloading the packaged software from the On-Line Store is also the way tostart if you want to acquire a more general (multiscreen, site, or corporate) license.• You can purchase media containing the programs from Cambridge UniversityPress. Diskette versions are available in IBM-compatible format for machinesrunning Windows 3.1, 95, or NT.

CDROM versions in ISO-9660 format for PC,Macintosh, and UNIX systems are also available; these include both C and Fortranversions on a single CDROM (as well as versions in Pascal and BASIC from thefirst edition). Diskettes purchased from Cambridge University Press include asingle-screen license for PC or Macintosh only. The CDROM is available witha single-screen license for PC or Macintosh (order ISBN 0 521 576083), or (at aslightly higher price) with a single-screen license for UNIX workstations (orderISBN 0 521 576075). Orders for media from Cambridge University Press canbe placed at 800 872-7423 (North America only) or by email to orders@cup.org(North America) or trade@cup.cam.ac.uk (rest of world). Or, visit the Web siteshttp://www.cup.org (North America) or http://www.cup.cam.ac.uk (restof world).xviLicense InformationxviiTypes of License OfferedHere are the types of licenses that we offer.

Note that some types areautomatically acquired with the purchase of media from Cambridge UniversityPress, or of an unlocking password from the Numerical Recipes On-Line SoftwareStore, while other types of licenses require that you communicate specifically withNumerical Recipes Software (email: orders@nr.com or fax: 781 863-1739).

OurWeb site http://www.nr.com has additional information.• [“Immediate License”] If you are the individual owner of a copy of this book andyou type one or more of its routines into your computer, we authorize you to usethem on that computer for your own personal and noncommercial purposes. Youare not authorized to transfer or distribute machine-readable copies to any otherperson, or to use the routines on more than one machine, or to distribute executableprograms containing our routines. This is the only free license.• [“Single-Screen License”] This is the most common type of low-cost license, withterms governed by our Single Screen (Shrinkwrap) License document (completeterms available through our Web site).

Basically, this license lets you use NumericalRecipes routines on any one screen (PC, workstation, X-terminal, etc.). You mayalso, under this license, transfer pre-compiled, executable programs incorporatingour routines to other, unlicensed, screens or computers, providing that (i) yourapplication is noncommercial (i.e., does not involve the selling of your programfor a fee), (ii) the programs were first developed, compiled, and successfully runon a licensed screen, and (iii) our routines are bound into the programs in such amanner that they cannot be accessed as individual routines and cannot practicablybe unbound and used in other programs. That is, under this license, your programuser must not be able to use our programs as part of a program library or “mix-andmatch” workbench.

Conditions for other types of commercial or noncommercialdistribution may be found on our Web site (http://www.nr.com).• [“Multi-Screen, Server, Site, and Corporate Licenses”] The terms of the SingleScreen License can be extended to designated groups of machines, defined bynumber of screens, number of machines, locations, or ownership.

Significantdiscounts from the corresponding single-screen prices are available when theestimated number of screens exceeds 40. Contact Numerical Recipes Software(email: orders@nr.com or fax: 781 863-1739) for details.• [“Course Right-to-Copy License”] Instructors at accredited educational institutionswho have adopted this book for a course, and who have already purchased a SingleScreen License (either acquired with the purchase of media, or from the NumericalRecipes On-Line Software Store), may license the programs for use in that courseas follows: Mail your name, title, and address; the course name, number, dates,and estimated enrollment; and advance payment of $5 per (estimated) studentto Numerical Recipes Software, at this address: P.O. Box 243, Cambridge, MA02238 (USA).