On 2010-04-26 03:30, Jay Litwyn wrote:
> Roger Alexander quoted a formula in fractint.frm
>
> GenInvMand_rjr { ; Jm Collard-Richard and rjr 2k03
>   c=z=1/pixel+p1:
>    z=fn1(z)*fn2(z+p2)+fn3(fn4(c))
>     |z|<=4
>     ;SOURCE: fractint.frm
> }
>
> ; Notice that fn3(fn4(c)) is a constant. In a re-entrant function, constant input yields constant output,
> ; so the formula can be sped up quite a bit like this:
>
> GenInvMand_rjr { ; Jm Collard-Richard and rjr 2k03
>   z=1/pixel+p1, c=fn3(fn4(z)):
>    z=fn1(z)*fn2(z+p2)+c
>     |z|<=4
>     ;SOURCE: fractint.frm
> }
>

  Thanx for the input. I modded this formula ages ago using the monkey at the keyboard approach-throw enough, something sticks! My grasp of fractal math is shaky at best and I will  rewrite

the formula before I use it the next time.

     Cheers,

      Roger