FOTD 09-01-04 (Fractal Ribbons [6])
FOTD -- January 09, 2004 (Rating 6) Fractal visionaries and enthusiasts: With today's image we return to fractal normalcy -- a rating of 6. The illustrated scene lies in the same parent that produced yesterday's image, and once again, one of the more exotic 'outside' options was used, this time the 'atan' option. I read somewhere recently, probably in a letter on the list, that the Fractint 'atan' function has an error somewhere in it. If so, it's a bit late now to correct it, since if this were done, images such as today's, which use the incorrect version, would no longer work. Of course, we could always save the incorrect version by giving it a new name, as was done with the 'cosxx' function. Or even better, we could give the correct version a different name. Today's image reminds me of the type of image that was so popular around 10 years ago, and resembled curled satin ribbons. I named the image "Fractal Ribbons" because of this resemblance. I rated it a 6 because, at least by my standards, it is a bit above average. I cannot say why I am staying with this particular parent fractal, which is giving me such a hard time. Maybe I want to prove that potential glory lies in every fractal, even the most humble. Well, I'll stay with the same fractal another couple days. If I find nothing in it by then worth a rating of 8, I'll give it up and move on. Today's image renders in only 4 minutes, making it a reasonable value for the time spent. Hmmm, maybe I'll start giving my FOTD images a 'value' rating. I could take the present 0-to-10 rating, divide it by the minutes needed to render the image, and multiply the result by 100. This would make today's image worth 150 value points. We'll see . . . The best value of all however is still downloading the completed GIF image from Paul's web site at: <http://home.att.net/~Paul.N.Lee/FotD/FotD.html> which can be done in a minute or so. The temperature reached 34F 1C here at Fractal central on Thurs- day, but clouds moved in by midday, making things too chilly for the sensitive whiskers of the fractal cats, who passed the after- noon curled by the radiator, sleeping peacefully. A bit of tuna in the evening made their day complete. This morning is start- ing cloudy and cold again, with a few flakes of snow in the air, and even colder air due by this evening. The fractal cats will not be happy about this. For me, today will be another forgettable day -- that is unless I find a fractal that rates an honest 10. Check back here in 24 hours to see if I succeed, but don't be surprised if I fail. Fractals that rate a 10 are as rare as dodo birds. Jim Muth jamth@mindspring.com jimmuth@aol.com START 20.0 PAR-FORMULA FILE================================ Fractal_Ribbons { ; time=0:04:07.60--SF5 on a p200 reset=2002 type=formula formulafile=allinone.frm formulaname=MandelbrotMix2 function=recip passes=1 center-mag=-0.61045250190546770/-0.011003094073171\ 64/2128.036/1/-142.5/-5.97177099437296022e-011 params=1.2/-2.1/-2.1/-1.2/0/50/0/0 float=y maxiter=1200 inside=255 outside=atan periodicity=10 colors=000NjAMiALhAKgAJfAKeAKdAKcALbBLaCL`DM_OMZFM\ ZGNYHNYINXJNXKOXLOWQOWQPWRPWSPWTQWUQWVQWWRWYRW_RWa\ RWcSWdSWeSWfTWgTWhTWiUWjUWkUWlVWmVWnVWnVWoWWoWWpWW\ pWWqWWrWWsWWtWWuWXsWXtWXtWXuWXvWXwWYvWYwWYwWYxWYxX\ XyWXxWXwVWvVWuUVtUUsTTrTTqSSpSRoRRnRQmQPlQOkPOjPNi\ OMhOLgOLfNKeMJdMJcLIbLGaKG`KG_JFZJEYIEXIDWHDVHCUGC\ TGBSFARF9QE9PE8OD7ND7MC6LC5KB4JB4IA3HA2G81F92EA2DB\ 2CC3BD3BE3AF3AG49H49I48J48K57L57M56N65O65P64Q64R73\ S73T72U72V81W81X80X80ZA2_B3`D4aE5bG6cH7dJ9eKAfMBgN\ ChPDiQEkSGlTHmVInWJoYKpZLq`NraOscPtdQufRvgSufRtfQt\ fQsfPrfPrfOqeNpeNpeMoeMneLneKmdKmdJldJkdIkdHjdHicG\ icGhcFgcEgcEfdDie5lf9ogDrhFrhGrhHrhHrhIrhJrgJrgKrg\ LrgLrgMrfNrfNrfOrfPrfPreQreRreRreSreSreTrdUrdUrdVr\ dWrdWrcXrcYrcYrcZrc_rb_rb`rbarbarbbv`crbbocbldbheb\ efbbgb_hbYi_WjYUkWSlUQmRPnPNoNLpLJqIHrGFsEEtCCu9Av\ 7XwKWwJVwIUwHSwGRwFQwFzzz } frm:MandelbrotMix2 {; Jim Muth a=real(p1), b=imag(p1), d=real(p2), f=imag(p2), g=1/f, h=1/d, j=1/(f-b), z=(((-a*b*g*h)^j)+(p4)), k=real(p3)+1, l=imag(p3)+100, c=fn1(pixel): z=k*((a*(z^b))+(d*(z^f)))+c, |z| < l } END 20.0 PAR-FORMULA FILE==================================
On Fri, 9 Jan 2004, Jim Muth wrote:
I read somewhere recently, probably in a letter on the list, that the Fractint 'atan' function has an error somewhere in it. If so, it's a bit late now to correct it, since if this were done, images such as today's, which use the incorrect version, would no longer work.
The problem is that someone hard-coded 180 degrees...er...colours into a function that _uses_ inverse tanjents. The simple fix would make that max_colours, so there'd be no difference to the user, except a wider raynj of colours. A more elaborate fix would let you _set_ the limit of colours in the imaje (in the blank where the number for a constant inside or outside colour would go). That wouldn't be a problem with old .par files, either, because the default could again be max_colors. (When outside=atan, this patchlevel five will change any numbers for that blank to zero). The major peculiarity with outside or inside=atan is that you can get max_colors with a single iteration. And with the escape values and iteration counts that you like, Jim, that particular experiment might be worth something. :-)
Of course, we could always save the incorrect version by giving it a new name, as was done with the 'cosxx' function. Or even better, we could give the correct version a different name.
Like I implied, the problem isn't as fundamental as the atan function itself. If you're bent on identical output for the same .par file, then you can set the default max_colors to historical values.
participants (2)
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Jim Muth -
SherLok Merfy