I haven't tried and I don't have a compiler. (I may have Visual Studio 6 on CDs somewhere, but would it work on Windows 7?) Would you like to email me your compiler output and I'll take a look. It sounds like those definitions should be in the QD library. Are you sure you're including everything that you need?
On 25 Mar 2014, at 06:41, "Paul" <pdeleeuw@deleeuw.com.au> wrote:
Hi Rupert,
I am keen to put in a moderate precision step between double and full arbitrary precision. Quad double sounds like a great solution.
I downloaded the quad double library but struggle to get it to compile under Windows. The main issue is to get the windows definition for things like:
QD_ISFINITE, QD_ISINF and QD_ISNAN. These may be defined for Linux, but not for Windoze.
Have you been able to build a library for Windows?
Please advise.
Thanks,
Paul.
---------------------------------------------------------- Paul de Leeuw Computers NSW Central Coast, Australia Email: pdeleeuw@deleeuw.com.au www: <http://www.deleeuw.com.au> ABN 72 360 822 562 ----------------------------------------------------------
From: fractdev-bounces@mailman.xmission.com [mailto:fractdev-bounces@mailman.xmission.com] On Behalf Of Rupert Millard Sent: Sunday, 9 March 2014 10:15 PM To: Fractint developer's list Cc: Fractint developer's list Subject: Re: [Fractdev] Sorry, but Fractint is not slowing, but rapidly dying
Synchronous orbit iteration is a technique for speeding up computation of escape time fractals. Came in version 20 - activated by an option. It would be extremely helpful for deep zooms.
If you want to do arbitrary precision fractals in your software, I would recommend a library like GMP, which is being maintained and targets modern processors. But I would probably try QD first. As you have said the obvious way to do it is to have selectable types single, double, long double, double double, ?double long double, ?triple double, ?triple long double, quad double, ?quad long double, and finally arbitrary precision for very deep zooms.
On 9 Mar 2014, at 01:20, "Paul" <pdeleeuw@deleeuw.com.au> wrote:
Hi Rupert,
I see no advantage to using arbitrary precision in chaotic oscillators as there is never a need to zoom in that far.
Actually, I wish there was someone who could assemble the original ASM code for arbitrary precision for the 32 and 64 bit platforms. I don’t know 80*86 assembler and hve no idea how to port it. Winfract is still about 2 – 3 times faster than ManpWIN once the precision of double is exceeded. However, ManpWIN has been able to zoom to far greater depth 10^ 1000 or so. However, it took hours to create a single pixel on my little laptop J
Maybe double double and quad double will give a far better compromise between depth of zoom and speed. Maybe we could add staged precision using different modes. If one was really keen, we could create a library of complex arithmetic functions that automatically selected the correct precision and was transparent to the fractal functions.
I like your youthful enthusiasm. I would love to see the old team up and running again.
One thing I would love to see is modularisation of FRACTINT. I get horribly confused with all the globals that hound my code. I would love to see libraries of functions that virtually stand alone. Let’s keep screen co-ordinates separate from the float values of plotted variables. Let’s define our libraries so we can use them in other applications. I really struggle with the megalithic functions in FRACTINT. Just a Paulian idea J
Best regards,
Paul.
---------------------------------------------------------- Paul de Leeuw Computers NSW Central Coast, Australia Email: pdeleeuw@deleeuw.com.au www: <http://www.deleeuw.com.au> ABN 72 360 822 562 ----------------------------------------------------------
From: fractdev-bounces@mailman.xmission.com [mailto:fractdev-bounces@mailman.xmission.com] On Behalf Of Rupert Millard Sent: Sunday, 9 March 2014 12:56 AM To: Fractint developer's list Cc: Fractint developer's list Subject: Re: [Fractdev] Sorry, but Fractint is not slowing, but rapidly dying
Synchronous orbit iteration isn't well exploited either. It should be "easy" to port it to arbitrary precision on Xfractint. Having said that I tried, and couldn't figure out how to begin - are the viewing coordinates passed around as strings?
Secondly "double doubles" and "quad doubles" (such as http://web.mit.edu/tabbott/Public/quaddouble-debian/qd-2.3.4-old/docs/qd.pdf) may be faster than arbitrary precision and they cover a very useful range of magnification for the Mandelbrot set. (Trying double long doubles and triple things may also be fruitful.)
I think there's some scope for further optimising the SOI algorithm itself. The interpolation is not conformal. I have no proof but I think conformal interpolation would be more efficient - after all iteration of a complex function is conformal.
Finally, SOI would play well with arbitrary precision / double doubles / quad doubles because the most significant bits may be the same and their products/sums may only need to be calculated once.
If I could just get started, I think I'd have lots of fun, trying this stuff out in Xfractint.
(I wonder if I used to be the youngest user of Fractint? Back in 1996, aged 10, using version 19.6 on a 486. It takes me back! I was happy looking at the pretty pictures. Never realised how much more there was to it - C programming, complex analysis, etc.)
Kind regards,
Rupert
On 7 Mar 2014, at 20:53, Nicholas Wilt <nicholas_wilt@hotmail.com> wrote: It saddens me, a bit, that Fractint hasn't "kept up with the times." The technological landscape certainly has changed since I sent in my contributions 20+ years ago. (I optimized Lyapunov and L-systems. My L-systems optimization took advantage of the way integer code never touched the FP stack, so I could load the engine state into the FP registers and leave it there as the L-system parser happily indirected pointers-to-function.) Companies are often willing to subsidize open source development if the project is aligned with their business interests, but I guess the economics of open source don't translate to rendering pretty pictures!
I have very little time these days, what with the family, working a demanding job at Amazon, and continuing a part-time life as an author (The CUDA Handbook, June 2013). But every once in a while, I get to wondering, What's up with Fractint?, find a copy of the source code, unpack it, and start looking around, and say Man, This code needs a LOT of work. I wouldn't even know where to start!
The name of the project is dated, of course - there are still reasons to use fixed point here and there, but performance isn't one of them. An optimized CPU implementation of a fractal generator would use SSE (or now AVX), have separate single and double precision implementations, and leverage multicore hardware. Fractals are extremely computationally dense, so are a good fit both for GPU computing and for clustering. It's getting a bit far afield from my own expertise, but open source compiler technology (LLVM etc.) has advanced to the point where the custom fractal engines likely could take advantage.
A modern project would put clear divisions of labor between the fractal processing, translating the iteration counts to images, and the user interface. It might be more efficient to start from scratch and migrate code (or ideas) from Fractint a bit at a time. But with the limited time I could invest in such a project, I feel a bit like one of the mice from The Bell and the Cat. http://en.wikipedia.org/wiki/Belling_the_cat
If it isn't already in bitbucket or github or some other open source repository, I'd encourage migration of the "latest" (such as it is) code base to one of those.
Date: Fri, 7 Mar 2014 14:27:14 -0600 From: Paul.N.Lee@att.net To: fractdev@mailman.xmission.com Subject: Re: [Fractdev] Sorry, but Fractint is not slowing, but rapidly dying
Timothy Wegner wrote:
No need to feel any sorrow about one of the oldest and longest-maintained open source projects, which by rights, was obsolete a decade ago. Mystery of mysteries, it's life continues on.
They said the same thing about COBOL decades ago, but I still see companies all the time looking for some of those old programmers (like me) that really know how to work with legacy applications.
FractInt will be around until the last of the old users have finally died, which hopefully will be a few more decades for some of us. :-)
Sincerely, P.N.L.
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