TweetFollow Us on Twitter

Dec 98 Online

Volume Number: 14 (1998)
Issue Number: 12
Column Tag: MacTech Online

Advanced C++ Algorithms

by Jeff Clites, online@mactech.com

Algorithms are at the very heart of programming. Fortunately, the C++ standards committee saw fit to include an algorithms library to work in conjunction with the container classes of the STL. Although immensely useful, this library really covers only the most commonly used, general purpose tasks, and for specialized applications you have to look elsewhere. This month we are going to take a tour of some powerful algorithm libraries that pick up where the STL leaves off.

Algorithms in General

There are a number of printed references for learning about algorithms and the theory behind them. Algorithms in C++, 3rd ed., by Robert Sedgewick, is a new version of a classic reference, full of lucid explanations and copious illustrations, and there is a freeware program, MacBalsa, which animates many of the algorithms from the book. The Art of Computer Programming series by Donald E. Knuth is the definitive work on almost all things computing, and it is referenced by just about any writing which mentions the word "algorithm." Numerical Recipes in C by William H. Press, et al, is another classic, with an emphasis on practicality, and the full text is available in pdf form for preview on the web. On the other hand, a page at JPL warns against using the code from Numerical Recipes as-is, so you might want to check out these sites in tandem. For your general algorithm needs, check out Netlib, Codepage, and Programmer's Oasis - they have descriptions and links to a plethora of code sources.

MacBALSA
http://www.eg.bucknell.edu/~zaccone/MacBALSA/MacBALSA.html
Don Knuth's Home Page
http://www-cs-staff.stanford.edu/~knuth/
Numerical Recipes Home Page
http://www.nr.com/
Why not use Numerical Recipes?
http://math.jpl.nasa.gov/nr/
Netlib
http://www.netlib.org/c++/
{Codepage 2.2}
http://www.iro.umontreal.ca/~ratib/code/
Programmer's Oasis: Algorithms, Data Structures
http://www.utu.fi/~sisasa/oasis/oasis-algo.html

Finite-State Machines

Finite-State Machines (or FSMs for short) are based on a mechanical model of computing, originating with the Turing Machine. Although conceptually simple, they are the natural way to express many computational processes, such as string searching or parsing. Object Mentor has code available for an FSM compiler, which allows you to define an FSM with a simple notation and then compile it into code for a set of C++ classes. (Also be sure to check out the cool "Game of Life" applet, Wator, on their home page.) Conveniently, Michael Schürig has done the work of preparing a Mac version of the compiler as a droplet, and it is posted on his web site.

Object Mentor Freeware by Email
http://www.oma.com/Offerings/catalog.html
Michael Schürig's Home Page
http://www.schuerig.de/michael/

Genetic Algorithms

Genetic algorithms are a class of algorithms for solving minimization or best-fit problems, and are especially useful for situations in which classic optimization techniques fail. They are so-named because their basic strategy mimics biology: to find the optimal solution, generate a pool of candidate solutions, take a selection of the best ones and "combine" these to generate a new pool of candidates, and repeat. Unlike other optimization techniques, their successful use often depends heavily on finding the right way to encode the problem, but if used correctly they can succeed despite the presence of local minima which plague other approaches. MIT's GAlib makes it easy to implement a variety of different genetic algorithm strategies, and TimGA is a program which graphically demonstrates the optimization process and lets you experiment with how various parameters effect performance. TimGA is PowerPlant-based, and the code is available online.

GAlib: Matthew's C++ Genetic Algorithms Library
http://lancet.mit.edu/ga/
TimGA Source Code
http://hyperarchive.lcs.mit.edu/cgi-bin/NewSearch?key=TimGA

Parsing

A surprisingly difficult task in compiled languages is to allow the user to input a mathematical expression in text form and then evaluate it. This is a trivial one-liner in interpreted languages such as Perl, Python, and Tcl, but C and C++ don't have access to their own parsers and compilers at runtime, so if you want to do this sort of thing you have to write an interpreter yourself. A helpful starting point is the Chipmunk Basic Home Page, which has a large collection of links to source code. In particular, check out interp2num, an expression evaluator which gives you a choice of allowing C-like or BASIC-like syntax for the expressions it evaluates. Also, the STL-Compliant Software Components Collection page has a tokenizer which can help if you want to start from scratch.

Chipmunk Basic Home Page
http://www.rahul.net/rhn/cbas.page.html
STL-Compliant Software Components Collection
http://corp.metabyte.com/~fbp/stl/components.html

Linear Algebra and Matrix Manipulation

Fortran is famous for high-performance computation, and there a number of well-known libraries for numerical and scientific applications. Although many of these may be available to C and C++ programmers as compiled libraries or by way of the Fortran-to-C compiler, you probably prefer to find true C++ implementations. These allow you to peek under the hood when necessary, and they make it easier to integrate with the rest of your application by providing an object-based interface.

Most of these libraries fall under the general heading of linear algebra, since many problems are naturally expressed in terms of matrices. NIST has developed a library called TNT, the Template Numerical Toolkit, which tackles the difficult problem of developing an efficient yet elegant library for matrix math. One of its design criteria is compatibility with the STL, so that its matrices can act as generic container classes. Oleg Kiselyov's library, called simply LinAlg, is worth a look as well. Even if you do not use it directly, it uses a number of clever programming techniques, such as lazy evaluation and specialized constructors, which are instructive in their own right. Finally, Newmat, by Robert Davies, is a large and well-documented library, and is suitable for working with larger matrices.

Mac F2C
http://www.alumni.caltech.edu/~igormt/Mac_F2C.html
TNT Home Page
http://math.nist.gov/tnt/
Oleg Kiselyov's LinAlg Library
http://hyperarchive.lcs.mit.edu/cgi-bin/NewSearch?key=LinAlg
Newmat09: C++ matrix library
http://webnz.com/robert/nzc_nm09.html

(Pseudo) Random Numbers

It's pretty common for programs to use random number generators, and some are more serious about it than others. (Are you designing a solitaire game or trying to predict tornadoes?) If you need something a little more random than rand() or QuickDraw's Random(), there are alternatives out there. It's ironic, if you think about it, that the better implementations call themselves pseudorandom rather than random, to explicitly acknowledge that you can't really generate truly random numbers on a computer without some extra hardware making quantum measurements. UltraLib is a fast random-number generator, with implementations available in 68K and PPC assembly. It claims to be random even at the bit level, and to have an extremely long period ( 10^356). Agner Fog has another implementation of the same algorithm, as well as an algorithm of his own invention, on his page. Robert Davies, mentioned above, has a random number class library, Newran, which can generate sequences following a number of distributions. Donald E. Knuth's page, also mentioned above, has a public domain random number generator, with code in C or Fortran for single or double precision.

UltraLib
http://hyperarchive.lcs.mit.edu/cgi-bin/NewSearch?key=RandomNumberLib
Agner Fog's Pseudo random number generators
http://announce.com/agner/random/
Newran02A: C++ random number generator library
http://webnz.com/robert/nr02doc.htm
Knuth: Programs
http://www-cs-staff.stanford.edu/~knuth/programs.html

Cryptography

I could certainly write an entire column (or several) on the topic of cryptography, so I will just give a brief pointer here. Bruce Schneier's Applied Cryptography is the definitive reference on the subject, and his Counterpane web site has information on two freely available encryption schemes which he invented, as well as a pseudorandom number generator.

Counterpane Homepage
http://www.counterpane.com/

None of these libraries are Mac-specific; some are fully cross-platform, some have Mac versions available, and some may require tweaking (although less tweaking, now that CodeWarrior has support for member templates). In any case, I hope they are useful starting points.

These and armfuls of other links are available from the MacTech Online web pages at www.mactech.com/online/.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

NetShade 6.3.1 - Browse privately using...
NetShade is an anonymous proxy and VPN app+service for Mac. Unblock your Internet through NetShade's high-speed proxy and VPN servers spanning seven countries. NetShade masks your IP address as you... Read more
Dragon Dictate 4.0.7 - Premium voice-rec...
With Dragon Dictate speech recognition software, you can use your voice to create and edit text or interact with your favorite Mac applications. Far more than just speech-to-text, Dragon Dictate lets... Read more
Persecond 1.0.2 - Timelapse video made e...
Persecond is the easy, fun way to create a beautiful timelapse video. Import an image sequence from any camera, trim the length of your video, adjust the speed and playback direction, and you’re done... Read more
GIMP 2.8.14p2 - Powerful, free image edi...
GIMP is a multi-platform photo manipulation tool. GIMP is an acronym for GNU Image Manipulation Program. The GIMP is suitable for a variety of image manipulation tasks, including photo retouching,... Read more
Sandvox 2.10.2 - Easily build eye-catchi...
Sandvox is for Mac users who want to create a professional looking website quickly and easily. With Sandvox, you don't need to be a Web genius to build a stylish, feature-rich, standards-compliant... Read more
LibreOffice 5.0.1.2 - Free, open-source...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
f.lux 36.1 - Adjusts the color of your d...
f.lux makes the color of your computer's display adapt to the time of day, warm at night and like sunlight during the day. Ever notice how people texting at night have that eerie blue glow? Or wake... Read more
VirtualBox 5.0.2 - x86 virtualization so...
VirtualBox is a family of powerful x86 virtualization products for enterprise as well as home use. Not only is VirtualBox an extremely feature rich, high performance product for enterprise customers... Read more
File Juicer 4.43 - Extract images, video...
File Juicer is a drag-and-drop can opener and data archaeologist. Its specialty is to find and extract images, video, audio, or text from files which are hard to open in other ways. In computer... Read more
Apple MainStage 3.2 - Live performance t...
MainStage 3 makes it easy to bring to the stage all the same instruments and effects that you love in your recording. Everything from the Sound Library and Smart Controls you're familiar with from... Read more

ReBoard: Revolutionary Keyboard (Utilit...
ReBoard: Revolutionary Keyboard 1.0 Device: iOS Universal Category: Utilities Price: $1.99, Version: 1.0 (iTunes) Description: Do everything within the keyboard without switching apps! If you are in WhatsApp, how do you schedule a... | Read more »
Tiny Empire (Games)
Tiny Empire 1.1.3 Device: iOS Universal Category: Games Price: $2.99, Version: 1.1.3 (iTunes) Description: Launch cannonballs and blow tiny orcs into thousands of pieces in this intuitive fantasy-themed puzzle shooter! Embark on an... | Read more »
Astropad Mini (Productivity)
Astropad Mini 1.0 Device: iOS iPhone Category: Productivity Price: $4.99, Version: 1.0 (iTunes) Description: *** 50% off introductory price! ​*** Get the high-end experience of a Wacom tablet at a fraction of the price with Astropad... | Read more »
Emo Chorus (Music)
Emo Chorus 1.0.0 Device: iOS Universal Category: Music Price: $1.99, Version: 1.0.0 (iTunes) Description: Realistic Choir simulator ranging from simple Chorus emulation to full ensemble Choir with 128 members. ### introductory offer... | Read more »
Forest Spirit (Games)
Forest Spirit 1.0.5 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.5 (iTunes) Description: | Read more »
Ski Safari 2 (Games)
Ski Safari 2 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: The world's most fantastical, fun, family-friendly skiing game is back and better than ever! Play as Sven's sister Evana, share... | Read more »
Lara Croft GO (Games)
Lara Croft GO 1.0.47768 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.47768 (iTunes) Description: Lara Croft GO is a turn based puzzle-adventure set in a long-forgotten world. Explore the ruins of an ancient... | Read more »
Whispering Willows (Games)
Whispering Willows 1.23 Device: iOS Universal Category: Games Price: $4.99, Version: 1.23 (iTunes) Description: **LAUNCH SALE 50% OFF** - Whispering Willows is on sale for 50% off ($4.99) until September 9th. | Read more »
Calvino Noir (Games)
Calvino Noir 1.1 Device: iOS iPhone Category: Games Price: $3.99, Version: 1.1 (iTunes) Description: The film noir stealth game. Calvino Noir is the exploratory, sneaking adventure through the 1930s European criminal underworld.... | Read more »
Angel Sword (Games)
Angel Sword 1.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.0 (iTunes) Description: Prepare to adventure in the most epic full scale multiplayer 3D RPG for mobile! Experience amazing detailed graphics in full HD.... | Read more »

Price Scanner via MacPrices.net

Big Grips Lift Handle For iPad Air and iPad A...
KEM Ventures, Inc. which pioneered the extra-large, super-protective iPad case market with the introduction of Big Grips Frame and Stand in 2011, is launching Big Grips Lift featuring a new super-... Read more
Samsung Launches Galaxy Tab S2, Its Most Powe...
Samsung Electronics America, Inc. has announced the U.S. release of the Galaxy Tab S2, its thinnest, lightest, ultra-fast tablet. Blending form and function, elegant design and multitasking power,... Read more
Tablet Screen Sizes Expanding as iPad Pro App...
Larger screen sizes are gaining favor as the tablet transforms into a productivity device, with shipments growing 185 percent year-over-year in 2015. According to a new Strategy Analytics’ Tablet... Read more
Today Only: Save US$50 on Adobe Elements 13;...
Keep the memories. lose the distractions. Summer’s winding down and it’s time to turn almost perfect shots into picture perfect memories with Elements 13. And get the power to edit both photos and... Read more
1.4GHz Mac mini on sale for $449, save $50
Best Buy has the 1.4GHz Mac mini on sale for $50 off MSRP on their online store. Choose free shipping or free local store pickup (if available). Price for online orders only, in-store price may vary... Read more
12-inch 1.1GHz Gold MacBook on sale for $1149...
B&H Photo has the 12″ 1.1GHz Gold Retina MacBook on sale for $1149.99 including free shipping plus NY sales tax only. Their price is $150 off MSRP, and it’s the lowest price available for this... Read more
27-inch 3.3GHz 5K iMac on sale for $1849, sav...
Best Buy has the 27″ 3.3GHz 5K iMac on sale for $1849.99. Their price is $150 off MSRP, and it’s the lowest price available for this model. Choose free shipping or free local store pickup (if... Read more
Worldwide Tablet Shipments Expected to Declin...
Does Apple badly need a touchscreen convertible/hybrid laptop MacBook? Yes, judging from a new market forecast from the International Data Corporation (IDC) Worldwide Quarterly Tablet Tracker, which... Read more
Continued PC Shipment Shrinkage Expected Thro...
Worldwide PC shipments are expected to fall by -8.7 percent in 2015 and not stabilize until 2017, according to the latest International Data Corporation (IDC) Worldwide Quarterly PC Tracker data. The... Read more
Imminent iPhone 6s Announcement Leads To 103%...
NextWorth Solutions, with its online and in-store electronics trade-in programs including http://NextWorth.com, reports that it has experienced a 103 percent surge in quoted trade-in values over the... Read more

Jobs Board

*Apple* Retail Online Store: Customer Insigh...
**Job Summary** Apple Retail (Online Store) is seeking an experienced e-commerce analytics professional to join the Customer Insights Team. The Web e-Commerce Analyst Read more
*Apple* Music, Business Operations - Apple I...
Changing the world is all in a day039s work at Apple . If you love innovation, here039s your chance to make a career of it. You039ll work hard. But the job comes with Read more
WW *Apple* Retail Online Store: Customer In...
**Job Summary** The Apple Retail - Online Store is seeking an experienced web merchandising analytics professional to join the Customer Insights Team. The Web Read more
Senior Payments Security Manager - *Apple*...
**Job Summary** Apple , Inc. is looking for a highly motivated, innovative and hands-on senior payments security manager to join the Apple Pay security team. You will Read more
Software QA Engineer, *Apple* Pay Security...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.