May 2004 - Fractdev - mailman.xmission.com

Athlon woes
by Tim Wegner 03 Sep '08

03 Sep '08

I built a computer last year using an Athlon with a Gigabyte motherboard. I had troubles with Fractint - with any SVGA mode the computer would hang after the completion of the image. I always assumed this was an Windows XP issue. Today I tried Fractint with freedos on the same computer, with the same results. So apparently it's an incompatability bgetween fractint and my compuiter. Truecolor, 320x200, diskvideo, and even tweaked modes work. SCGA modes fail, and only after the image completes. This behavior appears to have nothing to do with recent versions. Has anyone else had trouble with Athlon? Hmm, maybe I need to look at bios settings. Tim

7 21

Patch 6
by Jonathan Osuch 03 Jul '05

03 Jul '05

Tim, I'm going to try to wrap up patch 6 this week. So far, this is what I have: Fixed FPUcplxdiv and FPUcplxlog routines in fpu087.c to match assembler code. Fixed it so spaces are recognized in PAR entry names. Fixed evolver parameter entry. Fixed hypercomplex fractal type to turn off symmetry when a cj parameter is used. Fixed the plasma type to show the value of the parameter that is actually used in the image generation. Fixed the plasma type so that a parameter file uses the included colors instead of the default colors. Revised the plasma type prompt to reflect the values that could actually be used. Fixed inside=atan and outside=atan to use the full color palette instead of limiting to 180 colors. Modified the resume code to remove the Xfractint specific sections since they are no longer needed. I still need to move all this over to DOS and make sure nothing is broken. There are other fixes I would like to include, but haven't done them yet. Jonathan

3 6

Xfractint subdirectory display in menus
by Jonathan Osuch 14 Jun '04

14 Jun '04

Tim, I've made some progress getting subdirectories to display in Xfractint. It appears to work for most items, but not color maps. For some reason a slash is getting added to the color map name (Xfractint thinks it's a directory). So, color maps won't load. Jonathan

3 6

Question on acos function in Fractint
by Edwin 07 May '04

07 May '04

Hi, I'm comparing the results my fractal program produces against Fractint's. In general I get the same results, but I'm getting dramatically different images for some fractals involving the acos function. Using the formula: mandelfn { z = 0: z = fn1(z*z) + pixel |z| < 4.0 } With fn1 = acos and default parameters, Fractint produces : http://www.speakeasy.org/~edyoung/fract001.gif And I get: http://www.speakeasy.org/~edyoung/acos_image.png I think this stems from different functions we use to compute acos: Fractint uses rz=Arccos(z)=-i*Log{z+sqrt(z*z-1)} Whereas my code uses: acos(z) = pi/2 - asin(z) According to MathWorld, ( see http://functions.wolfram.com/ElementaryFunctions/ArcCos/27/02/01/) the formula Fractint uses is only valid for certain domains, so I'm suspicious that Fractint's producing the wrong output. Any comments? Regards, -- Edwin

2 3

Reading deep zooms from PARs
by Tim Wegner 02 May '04

02 May '04

A user sent me an example of a deepzoom PAR that won't reload into Fractint. I looked into it, and it wasn't hard to find the problem. I have a fix of sorts which I'll turn into a patch as soon as I get it cleaned up. Only cmdfiles.c is involved. I expect this is a known problem. Tim

2 9