Re: [Fractint] Image artifacts due to precision problems

Hal,

> Also, am I correct in assuming that arbitrary
> precision works for formula file fractals? <---<<

No, that is incorrect. It has been talked about, but has yet to be
implemented.

You can play with the mandelbrot fractal type with mathtolerance=-1/-1
to see the effect of the number of digits of (arbitrary) precision. Try
comparing the images generated with bfdigits=4 and bfdigits=8.

...
> Is the above procedure to compare two images
> in files correct? <---<<

Yes.

> It appears that the color map of the images
> is used to display the difference pixels.
> If there are extremely dim color map values
> in the image one could be fooled into thinking
> that there were no differences between two
> images when in fact there were if the
> difference pixels that were displayed happened
> to use dim color map values.

A file named CMPERR is generated that lists all the differences and the
color values from both images.

...
> Is it likely that I did this comparison and
> analysis incorrectly, or is this difference
> between integer and float expected? <---<<

Yes, I would expect to see these differences due to the different
precision between the integer math and the floating point math.

Jonathan