April 2008 - Fractdev - mailman.xmission.com

Paul?
by Richard 19 Nov '09

19 Nov '09

Hey, did Paul get CVS access? Paul, were you able to compile the branch with VC++ 2005 Express? I did put some tweaks in there to get everything to compile with no warnings on the Express edition. I haven't put a copy of VS.NET 2003 Academic Edition in the mail for you yet, but its coming... -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

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Athlon woes
by Tim Wegner 02 Sep '08

02 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

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I've run across what appears to be 2 problems with the 20.99.8 Fractint for Windows
by Hal Lane 02 May '08

02 May '08

I've run across what appears to be two problems with the ver 20.99.8 Fractint for Windows, one known, one perhaps new: - Calculating Jim Muth's FoTD for 8/4/8 gives a black screen using the "Run saved command set" command. - Completion of the image at 640x480 is essentially instantaneous per the <tab> command, instead of the 7 1/2 minutes described by Jim. - After calculating the FoTD for 8/4/8 and: - Choosing fractal "Type" "mandel" and - Accepting the default parms - An incorrect default Mandelbrot image is drawn. - The problem appears to be that the "Outside" parm on the "X" screen is left as "fmod" from the previous calculation of the FoTD using the "Run saved command set" command. - Changing "Outside" to "iter" draws the correct default Mandelbrot image. The first problem appears to be of the following type: Author: Richard Date: 2008-02-18 09:11 -500 Subject: Re: [Fractdev] <Richard> Lex & yacc for formula parser? > > ...I wouldn't mind fixing the bug that > > causes some formulas to render incorrectly in the near term. The second problem may be a newly uncovered problem. Calculating the FoTD for 8/4/8 with DOS Fractint ver 20.04.4 gives the correct image. - Hal Lane ######################### # hallane(a)earthlink.net # #########################

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shift by negative bits
by Richard 12 Apr '08

12 Apr '08

in unix/fpu087.c, RegSftFloat: long RegSftFloat(x, Shift) long x; int Shift; { float f; f = em2float(x); if (Shift>0) { f *= (1<<Shift); } else { f /= (1<<Shift); } return float2em(f); } When Shift is negative, it divides by 1 left-shifted by a negative number of bits. Shouldn't this be 1 << -Shift instead? -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

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save_stack() called without calling restore_stack()
by Richard 09 Apr '08

09 Apr '08

This looks like a bug to me. fractalb.c, ComplexPower_bf: _BFCMPLX *ComplexPower_bf(_BFCMPLX *t, _BFCMPLX *xx, _BFCMPLX *yy) { _BFCMPLX tmp; bf_t e2x, siny, cosy; int saved; saved = save_stack(); e2x = alloc_stack(rbflength+2); siny = alloc_stack(rbflength+2); cosy = alloc_stack(rbflength+2); tmp.x = alloc_stack(rbflength+2); tmp.y = alloc_stack(rbflength+2); /* 0 raised to anything is 0 */ if (is_bf_zero(xx->x) && is_bf_zero(xx->y)) { clear_bf(t->x); clear_bf(t->y); return(t); } cmplxlog_bf(t, xx); cplxmul_bf(&tmp, t, yy); exp_bf(e2x,tmp.x); sincos_bf(siny,cosy,tmp.y); mult_bf(t->x, e2x, cosy); mult_bf(t->y, e2x, siny); restore_stack(saved); return(t); } When the 'if' is taken above, restore_stack() is not called and bignum memory stack is leaked. This structure is repeated again in ComplexPower_bn. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

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