Raul,
thanks for the simplifications. I'had the idea to try power ^: for
Julia but it seems to add complexity.
I'll get the book.
Jan.

On Fri, Aug 12, 2011 at 3:48 PM, Raul Miller <[email protected]> wrote:
> P.S. here are a couple transformations of the raw code, aimed at simplifying 
> it:
>
> First, remove the dependence on the global DIM:
>
>
> julia=:1 : 0
> :
>       scale=.1.5
>       jx=.scale*((-:m)-x)%-:m
>       jy=.scale*((-:m)-y)%-:m
>       c=._0.8j0.156
>       a=.jx j. jy
>       i=.0
>       while. i < 256 do.
>               a=.(a * a) + c
>               if. 1000 < | a do. i return. end.
>               i=.i + 1
>       end.
>       255
> )
>
>
> This changes the invocation line to
> viewmat (i.DIM) DIM julia"0 0/ (i.DIM)
>
> Second, simplify the loop setup:
> julia=:1 : 0
> :
>       scale=.1.5
>       c=._0.8j0.156
>       a=. scale*1j1 - 2 * (x j. y)%m
>        i.255
>       for_i.i.255 do.
>               a=.(a * a) + c
>               if. 1000 < | a do. i return. end.
>       end.
>       255
> )
>
> That said, I highly recommend Cliff Reiter's book.
>
> That said, note that the link I sent in my previous message had a url
> that ended in a period.  But my mail client decided that that period
> was not a part of the url, which means the url did not function
> properly for me.
>
> Anyways, the name of the book is: Fractals, Visualization & J
>
> And here are a few urls for the book, which I am hoping will not be mangled:
>
> http://www.lulu.com/content/635966
> http://www.lulu.com/content/635938
> http://www.amazon.com/Fractals-Visualization-J-Clifford-Reiter/dp/1895721180
> http://www.amazon.com/gp/product/1430319801/ref=pd_lpo_k2_dp_sr_1
>
> FYI,
>
> --
> Raul
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>



-- 
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