Warp <war### [at] tagpovrayorg> wrote:
> On 05/19/2011 03:49 PM, gregjohn wrote:
> > In other words, we now have an artistic way to compare floating point error
> > between different machines.
>
>    The IEEE double-precision floating point format has 52 mantissa bits,
> and what you are seeing is hitting that limit. In other words, zooming
> any further would require more mantissa precision than that, and what
> you are seeing are the rounding errors caused by the mantissa not having
> enough bits.
>
>    The IEEE double-precision format is pretty common in most computer
> architectures, so they will all hit the limit at the same zooming level.
>
>    If the mandelbrot set were calculated using extended precision
> floating point numbers, which in the x87 have 64 mantissa bits, you
> could zoom a bit more (but not a lot) before hitting the artifacts.


Cool, thanks for the educ!   This one goes over a range (hi mag / lo mag) of
3.3E15.   How high can FractInt go??

You all may save me the embarrassment of asking someone with a more powerful
computer to run the code to compare. (Um, asking a second person).  While I do
work in computer hardware, it's on the purely physical side (processing
defects), not the system architecture side. But would every computer give the
same image for the floating point errors? Any coolness / art/ science in
comparing those?

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