ISSN 0964-5640
FRACTAL REPORT 19
Rabbits and Foxes Dolores Garcia Garcia 7
L - Systems John Sharp 10
Editorial and Announcements John de Rivaz 16
Double Position for Functions of a Complex Variable Paul Gailiunas 18
Taking Photographs of Computer Screen Images
Using Focal Plane Shutter Cameras Roger Castle-Smith 20
Fractal Report is published by Reeves Telecommunications Laboratories Ltd.,
West Towan House, Porthtowan, Truro, Cornwall TR4 8AX, United Kingdom.
Volume 4 no 19 First published February 1992. ISSN 0964-5640.
The article pile recovered a bit, but again is now fairly low, and I would be grateful for some contributions for the next issue, preferably before the end of February. The articles were a bit longer this time, but I hope that you enjoy them and the graphic images. I have regretfully had to hold over a few articles this time, so if one was yours, don't despair - it may appear next time!
Because of the popularity of Fractint, many readers would benefit from a regular column of articles on using Fractint, especially the Formula function. I look forward to receiving suitable material for publication in future issues. In the meantime I would highly recommend Fractal Creations, promoted with issue 17. We still have a few leaflets left if you have lost yours.
I would also be interested in material concerning the use of the Roland LAPC-1 PC sound card to generate fractal music, preferably using a compiled BASIC.
The results of our �300 advertisement were very poor from a financial point of view, with only a few subscriptions resulting. However there were over 50 replies, so one can't blame New Scientist. It appeared on 10 October.
Despite the poor timing of its launch, we have received a number of enquiries for paid space in our free-to-readers sheet Fractal Shopper and it is hoped that it will appear twice a year. It is hoped that the revenue earned by this will support Fractal Report and also enable us to remind people who have dropped out or failed to subscribe of Fractal Report's continued existence.
I hope that Dr Michael Ecker of REC won't mind me repeating a bit of his editorial in its latest issue, but I strongly agree with his sentiment. At the same time it will show what good value Fractal Report offers its subscribers:
Besides, I think the world has gone mad with the proliferation of those overpriced newsletters. Do any of you get the same "offers" that I get? One I got recently was from the Seybold group, with just one of its monthlies for a "mere" $295 per year, $100 off the usual $395. Another company offers its monthly newsletter of business communication for "only $432"; or Software Direct Marketing Newsletter at "just $495".
To which I would add that I have noted how many of those prices end in "95". Speaking of direct software marketing, how many of you get those tempting offers from Borland International, with hundreds of pounds knocked off their software prices. But they still seem to see a need to hide the true cost by quoting the price as so much plus a huge packing bill plus VAT. I am pretty sure that if you can't see round that marketing policy you'd never stand a chance of getting to grips with products such as their C++.
Reader's Hall of Fame
No entry again for magazine articles, I am afraid. I wish someone could get an article in New Scientist mentioning Fractal Report! But we are going to get another mention from Dr Pickover in a new book title unknown to appear in August. I have been sent a preview chapter concerning and DNA. It would appear that this book will be as good a read as Computers and the Imagination.
More from REC
REC, the recreational and educational computing newsletter produced a double issue in October. Featured on the front cover was a Halley map configured to produce a little "man" in its centre with arms, legs, ears, eyes, nose and two other round bits in a humorous position! This heralded a long article inside on the fundamentals of BLOAD/BSAVE and plotting images with GWBASIC. Maybe some think that in the days of Fractint all this is unnecessary, but those interested in education will find such articles essential reading. And this also applies to those who like to have the fullest possible control of their computers! A fractal Valentine Card program was also included as the usual diet of mathematical puzzles and similar material. Still no mention of the PI theorem though, the one that lets you calculate the digits from the nth digit onwards. (909, Violet Terrace Clark's Summit PA18411 USA)
And Another Issue of Amygdala
Amygdala 25 starts with a reprint of its piece of Math Fiction The Amygdalan Sects - slightly reminiscent of the strange doom-SF novels of J G Ballard. Of particular interest to Fractal Report readers is its main article, which details various methods of getting images from the interior of the Mandelbrot set, although many of these have also been covered in our pages. The other article is a description of The Secant Method, a mathematical process similar to Newton's Method, and which also generates a range of fractal images. These are presented in this issue as black and white prints and also in the colour slides which come with the newsletter. Their $30/rectangle advertisement page had nothing that I recognised as being new, and their 1991 fractal calendar is still for sale at $4.95 plus postage. It is well worth it for the colour images, some of which are by Ian Entwistle, and these can always be cut out and framed. I should have thought that they cost far more than $5 each to print. (Box 219 San Christobal NM 87564 USA)
As of 18 July 1991, their circulation had fallen to 518 subscribers. The circulation of Fractal Report at the end of this volume was 25% down on that at the end of the last volume, and maybe this heralds a decline in interest in fractals amongst computer enthusiasts.
Romanian Computer Magazine
From that issue of Amygdala, some news of a computer magazine starting in Romania. The organisers request help in the form of articles (or money!): Mr Marius F. Danca ProInformatica PO Box 524 3400 Cluj-9 Romania.
A Rival to Fractint?
A UK produced public domain PC program has appeared that claims speed improvements over Fractint in certain configurations. CAL fits on a 360K disk and will run in 250k of free memory. At present only the Mandelbrot Set and Henon Attractor are supported, but the program has been written so that other types will be introduced in subsequent editions (and possibly by the time this report appears). Also improvements scheduled will include 30,000 decimal places arithmetic for extreme zooms, data compression of saved images, more accurate image timing, and improved colour palette design. Copies are available for a blank disk and SAE, or �2.20 to include disc and postage. Overseas readers are asked to send a blank disk plus IRCs. Mr Timothy Harris 5, Burnham Park Road Peverell Plymouth Devon PL3 5QB.
More on FracGen 2
The Amiga program FracGen 2 now has different marketing arrangements since the last issue went to press. It is not public domain itself, but is sold by public domain libraries for a fixed price of �3.50. (IE although it is priced the same as the copying fee on some PD or shareware, you are not authorised to copy it and give it away to your friends.) Fractal Report readers may buy copies by post from Deja-Vu Software, 25, Park Road, Wigan WN6 7AA, ask for FracGen 2, disk no LPD36 and send �3.50 plus your name and address. I am told that the disk also contains a Fractal Report advertisement!
Chaos Theory Bulletin Board
Shareware by Telephone
Mr B.R. Holgate sent us details of the Cyberspace Gateway, a bulletin board system that claims the biggest shareware library in Europe, totalling 6 Giga Bytes. There are also teleconferencing systems, 200 sub-bulletin boards, shopping, classified ads, E mail, MPGs, MUGs, and virus checking. The system is available 24 hrs/day. The annual charge is a pound less than �100, or consumers can pay monthly @ �10 (annual total �120) (plus telephone costs to BT or Mercury, of course.) The modem setting is 300, 1200 or 2400 baud and Cyberspace will supply 2400 baud modems for 5p under �50. Tel 071-580-6433 (modem) or 071-323-1552 (voice), address 1, Malcom Drive Surbiton Surrey KT6 6QS.
Physics Software Includes Chaos Titles
Professor John S. Risley is the editor of Physics Academic Software and he has sent details of his range of products that include three titles that offer demonstrations of chaos theory for college lecturers and students. Two of them are collections of "interactive colourful demonstrations illustrating chaos in physics and biological systems". The third is described as a "utility that allows the advanced college physics student or researcher to perform interactive numerical experiments on nonlinear systems modeled by ordinary differential equations." Each title costs a shade under $70 and is for the PC. Educational users are warned that if more than one copy of the program is to be used by a class a site license must be bought. For ten users this costs about three times the cost of one program. Some of the other titles are being issued for the Macintosh and therefore it is reasonable to speculate whether this will happen to the chaos programs as well. For further details please write to him at the Dept of Physics North Carolina State University Raleigh NC 27695-8202 U. S. A.
Fractals in the Pop Music World
Mr Robert Wahlstedt sent a letter with his renewal joining in the discussion about fractal artwork on albums and CDs. He said that The Soup Dragons doesn't use fractal generated music, but they have used fractals in their videos. He said that many groups are using fractal art, including Mike Oldfield. There is a genre of music called "Techno" in Europe which uses a lot of fractal art, and fractal verbal imagery is used by a Swedish group The Butterfly Effect. Their titles include Deep Julia Dreaming and Seahorse Valley. But Mr Wahlstedt does not know of any group specifically using fractal methods to generate music. He suggests Fractal Report readers generating fractal music send in examples that we can put together to form a Fractal Report music cassette.
Shareware Shake-Up
PC-Star has issued a circular stating that it has further reduced prices to �1.50 per disk for one to one copying at 360K. If you chose 1.2M disks, they cost �2.50, but can contain the contents of up to three 360K disks. However there is a �1 surcharge per orders not paid by postal orders or cash. This is due to bank charges for inpayment of cheques, and furthermore non-members also have to pay an additional �1 per order. But if you do pay by cheque, make it out to "Paul Perera" not PC Star, as the company account will be closed. (Charges are higher for company accounts. - This goes to show bankers and other professionals that money grubbing loses custom in the long run.)
User supplied disks will be filled at a copying charge of �1 per disk.
Mr Perera believes that his operation offers the lowest prices ever for Shareware, but he is obviously having problems maintaining his business as he plans to review whether to continue at the end of 1992. So if you support low prices and business efficiency, then please support his company with your shareware needs this year.
He has an enormous range of shareware, including games, clip art, windows applications, programming languages and even a special "hot sheet" for "adults", available on special request.
Mr Perera also has some second hand books and PC software for sale at low prices. Contact him at PC Star, PO Box 164, Cardiff CF5 4SF, tel 0222 593476.
REM ****************
REM * CONCHA *
REM * *
REM ****************
REM José E. Murciano
REM Apdo. 192
REM 44080 Teruel
REM Spain.
SCREEN 9:KEY OFF:CLS
PI=4*ATN(1)
FOR C1=0 TO 15:READ C2:PALETTE C1,C2:NEXT C1
FOR I=0 TO 12*PI STEP PI/120
RC=EXP(I/7.5)
XC=320+RC*COS(I):YC=175+RC*.7*SIN(I)
FOR N=I TO PI+I STEP PI/120
Q%=ABS(16*SIN(N))
R=RC/2.75
X=R*COS(N):Y=R*SIN(N)
PSET(X+XC,.7*Y+YC),Q%-1
IF INSTAT THEN END
NEXT N
NEXT I
W$=INPUT$(1)
DATA 0,17,17,3,3,35,35,51,51,23,55,55,55,62,62,63
REM data 0,18,18,38,38,44,44,45,45,5,5,17,17,25,3,7
REM data 0,33,33,,21,21,37,37,53,53,39,39,47,47,55,55,63
REM data 0,61,8,33,41,43,51,30,54,46,60,36,37,45,5,13
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